So many storylines in automotive history can trace their origins to one series of events. The 1970s changed America’s automotive industry forever. In that decade, America started taking vehicle safety and emissions very seriously, while at the same time, multiple oil crises and general economic unease caused the entire auto industry to reset itself. Muscle cars, with their huge engines, insane insurance rates, and loads of power, became shadows of their former selves. That is, except for one car. Pontiac didn’t give up the fight, and for just 1973 and 1974, it produced the Pontiac Firebird SD-455, a big V8 Firebird that turned out muscle car power and performance while still complying with emissions rules.
Some publications break America’s muscle cars up into eras. Cars like the 1949 Oldsmobile Rocket 88 and the 1955 Chrysler C-300 are often considered pioneers of the muscle car, while the 1964 Pontiac Tempest LeMans with the GTO option package is usually regarded as the car that kicked off the first “muscle car” era. The madness would peak in 1970 with rides like the 450-gross horsepower Chevrolet Chevelle SS 454 and the 425-horsepower 1971 Plymouth Hemi ‘Cuda.
It wasn’t one single apocalyptic event that killed the first muscle car era, but several smaller cataclysms. In 1971, automakers began reducing compression ratios in an effort to get their engines to reduce nitrogen oxide levels and to prepare for the transition away from leaded gasoline. That year, another change was happening. For decades, automakers quoted Society of Automotive Engineers (SAE) gross horsepower numbers for their engines. A gross output came from an engine sitting on a test stand without any accessories, air filter, exhaust system, or transmission connected to it.
In 1971, Chrysler and General Motors began advertising two power numbers for their cars. SAE net horsepower showed what the engine put out when it was installed in a car and hooked up to everything. By 1972, SAE net was the industry standard. If you were an enthusiast, it might have seemed like your favorite car lost a whole heaping of horsepower overnight. The Hemi that powered the ‘Cuda? Its net rating was a milder 350 horsepower. The Chevrolet Corvette’s LT-1 V8 made 370 HP gross in 1970. In 1971, GM moved to net ratings while also lowering compression, bringing the Corvette’s optional mill down to a less exciting-sounding 255 HP. If this were the stock market, there would be a panic.
Despite everything, Pontiac was able to keep the good times rolling for at least two more years. Between 1973 and 1974, it built just 1,296 of its Firebird Trans-Am and Formula SD-455 coupes. While these cars might not have had the most impressive spec sheets, enthusiasts who got to drive them fell in love, anyway.
The Second-Generation Of An American Icon
The SD-455 was built on the second generation of the Firebird. Launched in February 1970, Pontiac’s F-body coupe was sold as the standard Firebird, the luxury Esprit, the hot Trans Am, and the Formula 400, which was a Trans Am alternative without a dramatic body kit. According to a MotorTrend article from early 1970, Pontiac was more or less trying to make an investment for the future with the Firebird:
In light of the current trepidations in the pony and muscle car fields caused by faltering sales, the rationale behind the new Firebird(s) is interesting. From their marketing research, Pontiac found that the average pony car buyer tended to be a young, single male, with the “pony” being his first new car. Less than half would buy another, but most would stay loyal to the manufacturer. Aha! Today’s Firebird owner is tomorrow’s Grand Prix buyer. So that’s what they mean in their “This is the beginning of tomorrow” jingle. At any rate, the many varied versions of the Firebird (in fifteen krazy kolors) reflects the effort to give the prospective pony car buyer all that he or she wants. They figured it all out with computers.
These cars came only as coupes, with a convertible unavailable for the entire generation. As MotorTrend wrote, the new Firebird was a departure from the first-generation, and few parts were shared between the two generations. At launch, the Firebird was available with three engines. The smallest was a 250 cubic-inch straight-six, which had 155 ponies at its disposal. Moving up from there netted you a 350 cubic-inch V8 and its 255 horses fed from a two-barrel carburetor.
The biggest engine available at launch was a 400 cubic-inch V8, which was offered in multiple tunes. The Esprit got the 400 in 265 HP two-barrel form, while the Formula 400 had the V8 making 330 HP in its base tune with a four-barrel carburetor. Optional to the Formula 400 and standard in a Trans Am was the 400 Ram Air III making 345 HP when equipped with a manual transmission. The hottest engine available in 1970 was the 400 with Ram Air IV, which made 370 HP with a manual transmission. These numbers are in gross horsepower, and engines paired with automatic transmissions had weaker outputs.
MotorTrend continues with the Firebird’s build:
The car is perched on a 108-inch wheelbase and spans a total length of 192.3 inches, up 1.2 inches from ’69. The front tread, at 61.6 inches, has also gained an inch, but the maximum width has been shaved a half-inch to 73.4. The hood has been lengthened, the deck shortened, the wipers and radio antenna hidden, and the side quarter windows and two headlights eliminated. The package is long, lean and clean. Using the firewall as datum and comparing the new ‘Bird to last year’s, the front and rear wheels have been moved ahead three inches. Effectively, the body was moved back on the chassis. The engine couldn’t go as far back as the body due to a crossmember in the front frame section, but is about two inches further to the rear, giving an additional inch ahead of the firewall. This is just enough to simplify checking the fluid level in the automatic trans.
[…]
The steering knuckles are made of malleable cast iron, and are identical in design to those used on the Cadillac. Independent, coil spring front suspension is used, with 10 percent stiffer springs on the Formula 400 and Trans Am than on the Firebird and Esprit. The higher powered cars also feature stiffer shock absorbers. All have a front stabilizer bar, 1.00-inch in diameter on the Firebird and Esprit, 1.125-inch in diameter on the Formula 400. The bar on the Trans Am is even thicker, 1.250-inch, the biggest one ever used on any Pontiac.
The rear suspension is based on multiple-leaf springs, with rates varying from 90 pounds/inch on the Firebird six to 125 pounds/inch on the Trans Am. These rates may seem fairly soft in light of the handling goals established for the car, but by increasing the driveshaft tunnel height, the engineers were able to allow greater vertical rear axle travel without danger of bottoming out. This results in a much-improved ride. The higher tunnel also separates the rear seats into two semi buckets, making the car strictly a four seater. New this year is the.620-inch diameter rear stabilizer bar, used to reduce roll and increase understeer on the Formula 400. A.875-inch bar is used on the Trans Am. Staggered mounting of the rear shocks, with the right one ahead of the rear axle and the left one behind, has been carried over from the ’69 models. All of this couples on the Trans Am to make it corner flatter than yesterday’s beer.
The Pontiac Firebird and its Chevrolet Camaro were well received. The Trans Am in particular remains an icon to this day, in part thanks to a starring role in “Smokey and the Bandit.” There are a handful of Pontiac Firebird “Holy Grails” out there, including the ultra-rare 1969 Trans Am convertible or the 2002 Pontiac Firebird Trans Am WS6. But there’s one more out there, the SD-455, and it involves an engine that traces its roots to racing.
The Pontiac Super Duty Program
As Hagerty writes, in 1956, Semom Emil “Bunkie” Knudsen took the top seat at Pontiac with marching orders to turn the brand around. At the time, Pontiac suffered from an image of being the brand for old guys. Knudsen would take a multi-pronged approach by giving Pontiac’s cars a more youthful appearance while also taking horsepower to the track.
Pontiac’s answer to competition was a program to put high-caliber Pontiacs on NASCAR circuits and NHRA drag racing. Technically, factory-supported racing was banned by the Automobile Manufacturers Association in 1957 after fatal crashes during the 1956 outings of the Indy 500 and the 24 Hours of LeMans. Automakers agreed not to advertise race wins, speeds, or directly support racing teams. But in an act of defiance, Knudsen and engineer John Z. DeLorean supported racing anyway, but in a backdoor, secret manner.
In 1959, Pontiac engineers took the firm’s 389 cubic-inch V8 and ironed out more power, specifically for competition use. The 420-A engine, as it was called then, featured 10.5:1 compression, 1.65:1 rocker arms, a four-bolt main block, a forged crankshaft, heat-treated valve springs, forged rods, a solid-lifter camshaft, high-flow heads, high-flow exhaust manifolds, and three Rochester two-barrel carburetors. The result was 345 HP, a 15-pony bump over the next-hottest 389 for 1959.
This engine, along with the whole program that created it, would become known as the Super Duty in 1960. Pontiac didn’t exactly advertise it, but racers scooped plenty of them up and used Pontiac Super Duty engines to rack up 30 out of 54 NASCAR Grand National wins by 1961. That was the year that DeLorean also became Pontiac’s chief engineer, and when Super Duty engines were available over-the-counter at dealerships.
Pontiac was rather busy that year, as it also created the even hotter 421 cubic-inch Super Duty V8, which churned out 405 horsepower. As Hot Rod magazine writes, this was also when NASCAR and the NHRA demanded that manufacturers put their go-fast parts into production cars. Pontiac obliged, and for the 1962 model year, the Catalina, which was a popular pick for racers, was available with the 421 Super Duty.
At least 50 Catalinas left the factory as a Super Duty, making it rare by any standard. Hot Rod and Hagerty report that Pontiac underrated these engines, so while they were claimed to have 405 gross horsepower, Super Duty engines actually made closer to 460 gross horsepower. The Tempest and Grand Prix would also see Super Duty options. General Motors put a stop to the Super Duty skunkworks not long after some Tempests had been christened as Super Duty cars.
No Replacement For Displacement
As Hot Rod writes, the Super Duty name would reappear in 1970. Engineers developed the 400 cubic-inch Ram Air Super Duty V8, which was adorned with round-port cylinder heads, a heavy-duty block, a forged crankshaft, and forged rods. This engine was supposed to go into the second-generation Firebird, but it was canceled before the vehicle’s launch, leaving the Ram Air IV as the top engine.
But the Super Duty wouldn’t remain dead for long. GM called for its 1971 model year engines to have a compression ratio of no more than 8.5:1 so they could run on low-lead gasoline. This put engineers into a bit of a pickle; their performance engines could have a ratio of 10:1. Reducing the compression ratio meant reducing power. Honoring the old idea that there’s no replacement for displacement, Pontiac put power back into its top V8 by upping its cubes. The 455 V8 was born, and the next step was to make it even hotter.
Hot Rod got to talk with the engineers behind the SD-455 engine, Pontiac Special Projects Engineer Skip McCully, former Pontiac engineer Michael Hicks, and tuner Nunzi Romano, and got the details of its development. From Hot Rod:
Testing of the Super Duty 455 began in 1970, and it shared many concepts with the Ram Air Super Duty. The four-bolt main block, which was cast at the Pontiac foundry, incorporated several unique features, making it better suited for extreme performance applications than typical production blocks. Its lifter valley received additional cross bracing, and the bulkheads received added material around the main saddles and oil-pan rails for improved rigidity. The rear of the block received a cast-in provision for a dry-sump oiling system driven by the camshaft, while a high-pressure, 80-psi, wet-sump oil pump was used in the oil pan.
Like the Ram Air Super Duty, initial plans for the Super Duty 455 included a forged-steel crankshaft, but it was ultimately rejected because of excessive cost. In its place went a standard-production, nodular-iron, 455 crankshaft. But rather than the typical finishing found on all other production units, Hicks stated the SD-455 crank received deep rolled fillets to increase overall strength and rigidity. Rolled fillets change the compression area of the journal by providing more side area for bearing contact, while the wider radius removes the sharp angle between the rod journal and counterweight, which could act as a parting line under extreme loads. According to Hicks, no additional treatments such as nitriding or shotpeening were ever performed on the SD-455 crank, contrary to what some sources have indicated.
Although cast iron was sufficient for the crankshaft, engineers saw the need for a connecting rod and piston capable of withstanding the most severe abuse. Michigan-based Continental Motors was contracted to produce a forged-steel connecting rod, while piston-specialist TRW provided the forged aluminum pistons. The rods were stock-length, forged-steel units that were heat treated and shotpeened for added strength while being checked magnetically for cracks several times throughout the manufacturing process. Pistons received a single-trough valve relief to boost compression and increase overall crown strength, while thicker piston skirts improved rigidity for high-rpm use. The round-port SD-455 cylinder heads were similar to those found on the R/A-IV and 455 H.O. engines but with revised intake and exhaust ports for even greater flow. Pontiac engineers redesigned the intake port to maintain constant cross-sectional area, and the result was a noticeably wider and taller port just past the intake flange. The pushrod bulge, normally 0.150 inch wide, was reduced so much that the pushrod passage in the head broke into the side wall of the intake port, and a 0.030-inch tube was pressed in to prevent leaks. Intake-port height increased so much the valve cover and rocker stud holes both broke into the port roof.
Skip McCully was in charge of making the power reliable. In his work, the SD-455 was dyno-tested to find the optimal fuel metering and ignition timing combination for maximum power. To ensure the engine didn’t blow up from detonation caused by poor-quality fuel or the use of incorrect octane, timing was then backed off by one percent off peak power.
The SD-455 engine was initially rated at 310 HP and fitted to Firebird test cars. Pontiac formally announced the SD-455 to the press in the summer of 1972. By this time, the flame of the muscle car had already been quickly dimming. Yet, the press and public’s response to the Super Duty cars was so strong that Pontiac decided to go through with it, anyway. Reportedly, some 600 pre-orders were placed for a Super Duty car.
The test Trans Am reportedly drove across the country to an Arizona proving ground, where it ran a 13-second quarter mile before getting emissions-tested. The engine passed the test by exceeding standards. However, since every engine can be slightly different, it’s possible that there could be an example that falls below standards. To ensure that didn’t happen, emissions engineers had to bake in a safety margin so that every engine would be compliant. Hot Rod continues:
To adhere to this margin, a camshaft with less duration and overlap was used. In place of the 041-style camshaft with 308/320 degrees of advertised duration, 0.470 inch net valve lift, and 87 degrees of valve overlap went a cam with valve timing identical to the 744 grind. Best known for its use in R/A III manual transmission applications, the 744 cam offered 301/313 degrees of advertised duration, 0.407 inch net valve lift, and 76 degrees of valve overlap. With less aggressive valve timing, power output was affected slightly–but not all negatively. Horsepower dropped from 310 with the 308/320 grind to 290 with the 301/313 cam, but torque increased from 390 lb-ft to 395 lb-ft, respectively.
[…]
Once the SD-455 was certified with the new cam, it was ready for production. But just when it appeared the car might finally hit the streets, it was further delayed by a recertification mandate affecting every Pontiac engine when the EPA found that part-throttle emissions were noncompliant. In March 1973, a running change was made, eliminating the timed solenoid that gave full vacuum advance and disabled the EGR valve in high gear after a specified amount of time. Only after this was corrected and the SD-455 recertified was the engine finally released for production in approximately late April 1973.
The changes between the SD-455 test cars, which were destroyed, and the production cars explain why you will find two different horsepower numbers for the SD-455 in articles and brochures. The brochures say 310 HP because they were printed before the engine was finalized. But the real output for SD-455 production units is 290 HP.
Likewise, brochures say that the Super Duty 455 was available in the Firebird, Grand Am, Grand Prix, and LeMans. However, the cost to recertify the engine twice for the Firebird alone was so much that it no longer made sense to recertify the engine for other models as well. As a result, the SD-455 was sold only in the Firebird and only in Formula and Trans Am trim levels.
The SD-455 Was Seriously Quick
In 1973, after years of development and headaches with government red tape, the Pontiac Firebird SD-455 went on sale. How was it? Car and Driver said that its Pontiac Firebird Trans Am SD-455 test car was the fastest Firebird in history. From their review:
You must reach a plateau of concentration where the machinery is even swifter. Go all the way back to 1968. Think of the Street Hemis, the L88s, the Boss 429s. When that era of unconcerned euphoria is locked in, sit back and get yourself comfortable to savor this progression of “performance” as determined in 1320 feet. Relish it as you would a Cuban cigar. And no fair looking ahead to the specifications page. We’ve checked with our lawyers, and they say it’s okay to tell you . . . if you can keep a secret.
On the seventh of February, 1973, our test Firebird Trans Am SD-455 swept through the quarter-mile at Orange County International Raceway in Irvine, California in an elapsed time of 13.751 seconds and at a terminal speed of 103.56 mph. That is fast. That, in fact, is outrageously fast even within a five-year-old frame of reference. And it was done in a street legal car—a 1973 street legal car—with a full tank of gas (3854 lb. curb weight), street tires and, wait for it . . . automatic transmission.
There was no cheering throng in the shut-off area, not a single pat on the hoodscoop for the over-achiever 1973 Trans Am. There should have been. The event was easily on a par with Don Garlits’ recent five-second runs in a fuel-burning dragster. It proves that once again, blindingly fast acceleration can be yours right off the assembly line. The secret password is SD-455. Simply check that option code on the order blank, and your Firebird will bristle with under-hood muscle. That is a rare quality these days, especially in a car which has the one-dimensional appearance of a Super Car, but which less ostentatiously has incorporated the subtle improvements that have traditionally sold high performance sport cars.
Car and Driver said that, according to its data, an SD-455-equipped Firebird could outrun Corvette 454s, Porsche 911s, De Tomaso Panteras, and Jaguar V-12s by nearly a second in the quarter-mile. In other words, it was a muscle car in an era that had otherwise left muscle cars behind. Yet, because of the great teamwork between engineers at GM, it still complied with emissions regulations.
A part of the magic appears to be the fact that, like the early Super Duty, Pontiac underrated the SD-455. In a modern dyno test, an SD-455 running on a stand achieved 396 HP and 477 lb-ft of torque.
In 1973, a Pontiac Firebird Formula had a base price of $3,276, while the Trans Am commanded $4,204. If you wanted the SD-455 package, that was another $578 on top of a Trans Am or $675 on top of a Formula. To put that cash into today’s numbers, a Formula was $25,760, a Trans Am was $33,057, and the SD-455 engine was between $4,545 and $5,307. Mind you, that money only got you the engine. You were still on the hook for the other options that you wanted.
Firebirds with the SD-455 were available either with a four-speed manual or a three-speed Hydra-Matic 400. If you wanted an air conditioner, the automatic was your only choice. According to Hemmings, most people got the automatic. Granted, not too many people chose any Firebird SD-455, as only 1,296 units were sold between 1973 and 1974. Of those, Hemmings says this is the breakdown:
Of 43 Firebird Formula SD-455s made in 1973, just 10 had four-speeds. Of 252 Trans Am SD-455s in ’73, only 72 had the manual transmission. In 1974, just 58 Formula SDs were made, and though a breakdown is not available for that car, just 212 of 943 Trans Am SDs had the manual gearbox that year.
This is one of those cases where a rare legend is actually worth pretty big money. Mint or numbers-matching examples of Pontiac Firebird Trans Am SD-455 and Pontiac Firebird Formula SD-455s can sell for over $100,000, and even higher-mile examples can still sell for over $50,000. As Hemmings writes, the purchase price is only the start. Since these cars are so rare and have unique parts not shared with other Firebirds, parts can run you well into the four or more to obtain.
The Swan Song Of The ’70s Muscle Car
Thankfully, muscle cars weren’t made fully extinct in the 1970s. Dodge would later make a muscle car with the body of a pickup truck, and after, other manufacturers would follow in Pontiac’s footsteps in making fast cars that still hit emissions standards. Nowadays, a car with 290 HP that could run a quarter mile in 13 seconds would be seen as somewhat tepid.
But for the 1,296 owners of an SD-455, it must have felt like being at the top of the world. It was the car that could stomp GM’s own Chevy Corvette, and so rare that nobody else at a car show was likely to have one. Today, you could also say that you own a Super Duty that isn’t a Ford pickup truck.
To some, the Pontiac Firebird SD-455 was the swan song of the first muscle car era. It had all of the right parts, from the pony car body with a stupidly huge engine to high power just for the sake of fun. It then laid waste to the competition, all while looking resplendent in its groovy graphics and fetching colors. While perhaps not as iconic as a black Trans Am with T-tops and a gold fire chicken, the SD-455 was a bright spot in a rough period in American automotive history.
Top photo: Pontiac
A friend in high school had a boss with a Formula-455. It was sporting really crappy tires (Goodyear STs). My friend, a big time gearhead, knew what a 455-SD was and told his boss “you know, if you put some decent tires on that, it would fly.”
To which his boss replied “Son, this thing is over 15 years old and has around 500 ft-lbs of torque. If I step on the gas too hard, something is going to break. I’d rather it be a cheap seat of tires, than an engine mount, a transmission or a rear end.”
One of my college cohorts had a super duty Firebird Formula SD455. Her boyfriend helped her to figure out out to order it. It was dark blue and the envy of the commuter lot at our school.
definitely a good read, the trick to these back in the days was to undo the timing and cam changes, I think it was called super tuning them. It unlocked the true potential. though I imagine having to run High octane gas in the 70’s was probably a pain in the butt after a while.
Pontiac’s Super Duty program was kind of the secret menu where, if you were in the know, you could do things with engines mere mortals had never even heard of.
If you knew the right numbers you could order up a block, head, and the internal parts and build what looked like, for instance, an Iron Duke…right up until you started it. Then it sounded like something else entirely.
Curious as to why this article didn’t show up on a Pthursday.
Did we give up on that already?
It’s urgently breaking news from 1973.
TBH, a lot of Pontiac news is old. Unless they bring back Pontiac. Then it will be new(s).
Pontiac news is olds(mobile)
What great writing and a fantastic read.
Thanks, Mercedes!
Wow, an extremely well researched article on my favorite dead brand. If only Pontiac hadn’t completely lost the plot somewhere in the ’90’s we’d still have some great American muscle to enjoy.
Mercedes, you’re rapidly becoming my favorite automotive journalist. Well done.
I have always assumed that the 290 net horsepower that these had was more than all but a handful of the cars from the late 1960s actually had. The barely streetable LS6 454/427 Tri-Power Corvettes and the Hemi/440 6-Pack Barracudas? Sure, they probably had more. Anything else? Nah. That being said:
On a stand with open long tube headers, no air filter and no engine accessories is basically the definition of a Gross horsepower reading, so… no. I’m sure that’s not true at all just like all the other nonsense about how muscle cars in the 1960s before emissions killed them secretly made more power than anything from any country until the mid-1980s but were only rated at some arbitrary low number isn’t true.
Especially since the Car and Driver/Hot Rod test car was before Pontiac had to take it back to the lab a to pare it back a bit when the EPA found out they were cheating on their testing and has long been considered a ringer in the first place so isn’t particularly indicative of the performance of the road cars people bought when Pontiac finally got it to pass through emissions. It these were pushing 400 horsepower at the crank they would be a lot faster than even the test car that made the rounds in 1973 was.
I saw the link to the dyno and was hoping it was a completely stock car on a hub dyno and then got disappointed when I saw the setup itself.
Not really. Tire sizes and tech were a hell of a lot different back then. Modern drag radials would make a huge difference.
That’s not how this works. Sidestepping that the car being tested was a 3-speed auto with an LSD and probably didn’t have much of an issue with launches to begin with (or that when Hot Rot tested the same car it went even faster but trapped the same), cars with allegedly 400 horsepower and 3800 pounds would not only be trapping at 103 miles per hour in test cars that were already quite a bit faster than the production ones the public got their hands on. They’d be trapping closer to stuff like early C4 ZR-1 Corvette and Ferrari Testarossas; because trap speed is largely a solved problem, with a formula and everything. And that test car in 1973 was already a fair bit faster than the ones Pontiac was selling to people, because the finished production version you bought from Pontiac when all was said and done was a high 14s @ high 90s car rather than something that could outrun an LS1 Camaro.
The fact of the matter is that the engine installed in a 1973 SD-455 that someone owned in 1973 is not that same engine on a stand with no air filter, engine accessories or exhaust. It is not the same engine as the one with a different cam and different heads and different compression and different air intake that was in the preproduction test car that Car and Driver and Hot Rod both were driving around in early 1973. When you bought a production SD-455 your engine did not “actually” put out 396 horsepower and Pontiac (for God knows what reason) was just secretly derating it while they were already being specifically watched by the EPA for trying to cheat on emissions while certifying it for sale in the first place and had to officially rate it less than they originally announced and install it in fewer cars and making it more expensive. The performance Pontiac managed to put in the cars it sold to the public would not propel a 3800 pound+ Trans Am with an automatic transmission down a quarter mile as fast as a 911 Turbo of the same era.
In 2026 we should be well past the point where we should be listening to automotive conspiracy theories that are pushing 60 years old and should be taking the cars of this era on what they were actually capable of, because there were ones like this that were notably performant for the time. That’s not “they stopped measuring on the dyno and this large displacement V8 actually revved as high as a contemporary Ferrari V12.” That’s not “if you change the cam and yank the muffler and disconnect the air conditioning pulley and port/polish the heads and dump so much fuel into the carb that it barely idles it shows that from the factory it was making way more than they said but insurance companies made them rate it less.” That’s “the doofus with a 390 Mustang who thinks he’s Frank Bullitt would be equally embarrassed by a V6 Accord from 2006 as everything else of that era except the cars actually engineered with sporting intent with the best drivetrains you could get would be.”
It was impressive that Pontiac pulled out all the stops to make an engine pass emissions using extremely crude early methods while still being very performant for the time period even though Chrysler had given up entirely and Ford’s idea of competing was to add a quarter ton and 12 inches of overhang on a 105 horsepower Pinto. That low compression engine still managed to make a car that would have been faster than a vast majority of the allegedly more powerful muscle cars from the decade prior. In the 1970s they made sure you could always properly spec a Trans Am to be every bit of an equal to a Corvette even as Chevrolet wasn’t sure they cared about that for the Corvette; and that’s extremely commendable. But it isn’t a pair of Pilot Sports away from being competitive with a Kia Stinger.
What fucking conspiracy? If you think G7014 bias ply tires gripped as well as modern tires, you are completely clueless.
Yes new engines are light years from the old ones but saying that this”because the finished production version you bought from Pontiac when all was said and done was a high 14s @ high 90s car rather than something that could outrun an LS1 Camaro.” Is stone cold retarded.
I take it you were not alive back then? Because what guys usually did by the mid 70s is install an HEI dist and some bigger back tires (if you think that an LSD could hold on to that much tq down low, you have not driven one) and maybe some richer primary jets that made a big difference.
Get a clue.
The conspiracy that these cars, even probable ringers like the specific preproduction car that Car and Driver and Hot Rod both tested, were actually even faster than the tests they had at the time suggested, which only makes sense if you’re trying to repeat the same nonsense from the 1960s and 1970s that they were somehow secretly putting out power figures comparable to modern cars even though that wasn’t reflected in any of the testing they had done on them at the time.
The Car and Driver and Hot Rot test car didn’t have bias ply tires on it.
Incidentally 15 flat at @ 98 is exactly what Motor Trend got with their production example of the car later that year.
Now, I dunno how well “Get a clue” was supposed to land as a retort coming from someone who made sure to insult me twice but couldn’t be bothered to read the first two sentences of what was being responded to, but I’ll spell it out for you to try and help you anyway: Unless you’re insinuating that the car with an LSD, 3 speed automatic with 3.42 gears and 3800 pounds to haul was lighting up its tires all the way down the drag strip (when Car and Driver’s review basically said the opposite and Hot Rod’s test of the same car was quicker but had the same trap speed), trap speed is a function of horsepower and weight. Not traction (outside of extreme tire spin). Not tire quality.
Horsepower.
Weight.
HP=W×(V/234)^3.
There have been calculators online for this shit for the entire 25+ years I’ve used the internet, so none of this should be news to a guy like you so willing to throw your toys about what 50 year old cars do at a drag strip.
This car as delivered to people to buy has 290 horsepower give or take. It did not have 396 horsepower. It never had close to 396 horsepower, no matter what the one on a bench with no accessories, air filter or exhaust says. The specific preproproduction car that Car and Driver and Hot Rod both tested that had a hotter cam and higher compression and better air intake than the production car also didn’t have 396 horsepower, but it very likely had a fair bit more than the claimed 310 and has been rumored for years to have been a bit of a ringer on top of being from before the car was detuned to try and pass emissions.
So let me ask you directly:
Why is a car where the instrumented Car and Driver testing linked in the article (though I had to track down the full one) says is fairly easy to replicate results dramatically limited by traction to the effect that it would hurt its trap speed?
Why does the Hot Rod magazine test of the same car which was a couple tenths faster through the quarter have the same trap speed?
Why would better tires increase the trap speed at all for a car that was said to be easy to do replicate quarter mile results in and already didn’t improve in another instrumented test that had a notably faster ET?
I know the answer to these questions even though I’m apparently a clueless retarded guy (even the suspiciously fast test car that Car and Driver and Hot Rot tested didn’t have anywhere near 396 horsepower). I’m still curious, however, what you think the answer is. I’m sure you’ll just say “it just needs better tires” for a third time but maybe you’ll surprise me.
Thanks for sharing this incredible piece of automotive lore; a fantastic read from start to finish!
gtu
I was at Fermilab in Batavia, Illinois back in 1985 for a lecture or something and way at the far end of the parking lot was what looked like a basic brown Firebird, but with a shaker scoop. Being an absolute Pontiac fanatic at the time, I drove over to take a look. It was fairly rusty but once I saw the VIN had U87X in it, I knew I was looking at a genuine 1973 Super Duty Formula.
Was this at Wilson Hall? Some of those physicists have pretty cool cars.
Yep, My buddy and l used to go there a couple times a week for various youth programs they had back then. Being teenagers, we used to race each other up the staircase to the 15th (?) floor observation room. I even saw Hawking in Ramsey Auditorium with my high school physics class.
How does “three Rochester two-barrel carburetors” work with a V8 engine?
That’s 6 barrels to fuel 8 cylinders. My brain can’t figure this out.
I believe it is similar in concept to a single 4 barrel carb but more extreme. All 3 of the carbs feed into a single intake that feeds all the cylinders (It may be split side to side so that one of each of the two barrels feeds 4 cylinders). In normal driving only the center of the 3 is working. When you get hard on the gas pedal a mechanical or vacuum system opens up the other 2. So basically, it’s like having a small carb for driving around town and a much bigger carb for going fast.
A 4 barrel is similar in that the 2 front venturis are smaller and used 90% of the time, the rear pair are larger and only used at or near full throttle.
Thanks, that makes sense.
I thought each barrel served a certain number of cylinders (I’m a Brit and I’m used to a pair of Weber twin-chokes on a 4-cylinder engine). A with a 4-barrel on a V8 I assumed that each barrel served two cylinders, which is why I couldn’t figure it out.
But your explanation has helped a lot.
(similarly, I remember an episode of Wheeler Dealers where they put a 4-barrel carb on a V6 engine on an Alpine A310 and I couldn’t figure that out either)
If you’ve ever heard someone refer to the secondaries opening, that would be referring to the rear barrels. Most V8s were designed for low rpm use with lots of torque and low redline (didn’t usually need it) where flow characteristics differ than at high rpm and things like accurate fueling aren’t as fussy, prioritizing tractability and reliability. The high performance V8s get all the attention, but they were the exceptions. Most V8s were used to move family vehicles and even most pony cars were I6s or smaller V8s in the lower state of tune. About the only time you’d see a choke/barrel per cylinder would have been on decently funded teams running road races as it’s pretty expensive when talking about 8 cylinders and a small production run or custom intake(s). Multi-carb setups required more fussing to keep in tune, so the usual path of increased fueling was just a bigger carb and tuned intake (longer runners for lower rpm, shorter for higher). Jet travel was still an expensive luxury and the interstate system was a modern marvel people wanted to explore, so a big engine that could waft a 3-row land yacht full of kids on a toe-tickle of torque was what a lot of people wanted. Most other places didn’t have the luxury of cheap fuel, had heavy taxes on displacement (or, in the case of the UK, the bore, pushing engines to be designed for a longer stroke, which became a characteristic they were known for and probably helped popularity in the States where lower end torque was the norm), and had less need/desire for traveling as long distances, so they went for rpm to get power.
Adding on to this, this is another reason beyond just price why the more “exotic” domestic V8s tended to have low adoption rates vs just the big engine turning slowly, because they were tricky to keep them running well.
Hemis and Tri-Power 427s and even the Six Pack 440s were fast and powerful and were way happier when beat on throughout the rev range than your typical 428s or 454s or 440s but they were lumpier and worse mannered at lower RPMs when the carbs were running correctly and Jeb down at Jiffy Lube probably didn’t know how to make that happen in the first place.
Yeah, that’s a good clarification and add. I remember even the usual suspects at cruise nights decades ago talking about how stuff like tri-power was cool, but not worth the hassle. It seems a bit of art to tune them properly by ear. I never tried it, but I don’t think I’d be good at it, especially not with built up hearing damage over the years. A single big carb got most of the way there for cheaper and little effort. In the real world where engines probably weren’t kept in top tune, they were likely even faster much of the time.
The 455 SD debuted in my middle teen years. The most colorful memories I have from this era revolves around an Irish-American family of seven boys and four girls.
The family owned a huge construction company. At the time, four of the sons and three daughters were driving age. The boys all drove Firebirds and the girls drove Camaros.
The two younger brothers of the four drivers each had a Trans Am one year apart. One had a 455 HO mill and the other a 455 SD. They were always racing each other and when they weren’t they were fistfighting over which engine was better. It was almost funny.
The whole family was pugnacious and frequently involved in fights at parties, but if you were quick witted, as they’d get liquored up and rowdy, you steered conversation toward which 455 was superior, then they’d take out their aggressions on each other. Woe to the idiot who disparaged all Firebirds, though.
The sisters and their Camaros are a story for another time.
There was an SD-455 in our SCCA autocross club in the 80’s. The car was seriously fast and well driven. The driver won the F-Stock nationals back then.
I love that 70-37 body style and that green 73 super duty is one of the best color combos for those years.
Side note the 79 Formula we got last year has a 455 (bored to a 468) that replaced the measly 301 it originally had and it is such and fun but also relatively smooth car to drive. Though currently it is having some weird bogging issues in 3rd and 4th gear (1st and 2nd are fine though) so assuming carb issues.
Split-nose F-body is best F-body, whether Firebird or Camaro. The 1977-78 “mean look” Firebirds, as made famous by the guy in my profile picture, are the only other ones that look as good.
For me with 2nd gen I prefer the 77-78 (mostly due to your profile pics movie hah), then 70-73, then 79-81 (Though with these I rather front end swap to a 77-78 as I prefer that front nose better but like the 79-81 taillights better) and lastly 74-76 I really just do not care with how they did that front end. No idea how they went from the earlier aggressive muscle look to that soft look.
Which is why I’ve always said that 1974-76 are the only two years that the Camaro looked better, for the entire history of both cars. Pick any other model year at random between 1967 and 2004, and the Pontiac version always looks better than the Chevrolet version. Always.
I worked with a guy with a gold late 70s Firebird with the 455. What was interesting is that his car came factory with an Olds Engine. Not sure why Pontiac used some Olds Ends for their last big block Firebirds, but there it was. Much more of a cruiser than a bruiser with that Olds 455.
Oh, Mercedes, my sweet, you done went and did it now – you featured my very favorite American car ever made by anyone ever, a Grail so Holy I never even bothered submitting it as a suggestion for this feature, because I thought everyone already knew. I’m so glad you put it up on your own. Thanks for painting the complete picture of the environment in which this engine was released, the very earliest dawn of “the malaise era.” The entire automotive ecosystem was conspiring to murder American performance, while Pontiac, just doing Pontiac things, as Pontiac did, said, “F it. Tonight we’re gonna party like it’s 1969. Just send it.”
It’s just another data point that proves that most, if not all, of your favorite GM products were the result of a given motor division sneaking around behind the General’s back and doing stuff they weren’t “allowed” to do. They weren’t great GM products because of GM, they were great GM products DESPITE being GM products, because if there is one truism about American cars, it is this: No matter the situation, the General, at all times, every day in every way, is always gonna General. And most often, that division was called Pontiac Motor Division. It’s only because Pontiac defied GM that the 1964 GTO launched the muscle car era in the first place. Ironically enough, as often happened, Pontiac breaking the rules handed GM a license to print money for the better part of the next decade. Now how about that.
Considering the time, the place, the set, and the setting, it is a pure miracle that this engine ever saw the light of day, even with production under 1300 units. And yeah, the factory numbers were fudged pretty hard. “Day two” engine mods could vault these things deep into the 500s for horsepower. And I’m still mad the “Colonnade” Grand Am/Lemans/GTO never got one.
For me personally, the holiest version of this Holy Grail? A 1-of-3-made 4-speed in Brewster Green, a one-year color from 1973. Pontiac made better greens and blues than anyone, and it’s a shame that color was only around for one year. Make mine with a saddle interior and rolling on honeycombs, please, precisely like this one, which was my laptop background photo for years.
https://images.mecum.com/image/upload/c_fill,f_auto,g_center,q_auto:best,w_1920/v1669823128/auctions/da14/da0914-193722/311438_1.jpg?
1st Joe excellent reply!
Re: “most, if not all, of your favorite GM products were the result of a given motor division sneaking around behind the General’s back and doing stuff they weren’t “allowed” to do. They weren’t great GM products because of GM, they were great GM products DESPITE being GM products”
I think there are a LOT of examples from all over the automotive world where this is true…
Two examples that come to mind…
The VW GTI started with a small handful of passionate factory engineers working late / in secret with VWs small, light weight economy car*…
BMW 2002 Tii I think started the same way
Oh and Ford putting the glorious 3.0 Yamaha engineered v6 in to the Taurus to create the original SHO too
Im certain there are more examples out there like I said these are a few that come to mind.
*I would <3 to see this story told here!
Whoa! Please warn me when you’re going to post a link to something so unexpectedly stunning!!! That color! Those wheels!! That bumper-free split grille!!! Ducktail spoiler!!! And it’s stock?! (Bumper-delete excepted)
Heh. The 1970-73 Firebirds had no front bumper at all, or at least not a chrome one – just the Endura nose. And yep, that’s precisely how that particular car would have looked when it rolled off the transport in 1973. Time has indeed been kind to the old ‘Bird, hasn’t it?
Thanks! I just tried to edit my comment to acknowledge that, but too much time has passed.
Hey Joe (apologies to Jimi), the car in the top shot is almost identical to the car I ordered and bought new: ’74 TA, SD-455, 4-speed, Buccaneer Red, Honeycomb wheels, but with a black interior and Uniroyal Tiger Paw tires. I never drove it in winters, it was rarely rained upon, and when I became a broke college student a couple years later I traded it to my brother for a daily driver. My brother has it to this day along with his other cars, and has taken immaculate professional care of it. In the two years I owned it, I autocrossed it a couple times, did a road trip from Michigan to Colorado and back, and thoroughly enjoyed it. The bark of that SD through the crossflow exhaust system while rowing through the gears is a delight!
Mercedes, thanks for the great write-up!
> most would stay loyal to the manufacturer
This mantra seems lost in a market where fewer small “cheap” or “fun” cars are accessible as a first vehicle.
That mantra is no longer true and hasn’t been for a long time. Today buyers jump from brand to brand and repeat loyalty across the industry is about 50%. The biggest exception is truck buyers.
People like my father-in-law are a rare exception. He has always bought Ford’s and bought them new. He is having a bit of a crisis right now because my mother-in-law was t-boned and here 2024 Escape totaled. She wants another Escape but they are no longer made. He doesn’t want to buy used and is too much of a cheapskate to buy one of the higher trim 2026 models that are still on dealer lots. Even those are rare, I could only find about a dozen in his state.
I’ve definitely gone back to brands that I had good experiences with, when I was younger.
I’ve also gone back to brands that I’ve had a good experience with before. However, decisions are made based on data and the average car buyer is not loyal. This is one of the reasons automakers are no longer willing to sell small or cheap cars at no margin or a loss with the hope that buyer will come back in the future and buy another car.
I do, too, and I think a lot of people do, but the kind of blind brand loyalty even after having bad experiences that was prevalent in the past is largely gone. Entry level cars were so cost-cut, too, that they weren’t something that tended to encourage brand loyalty at all if a customer wanted to move up tiers. Something like a Firebird made sense, though, as the demographic young man buyer was probably only giving up his ‘Bird because he started a family, but still wanted something of what he liked in that car in the bigger vehicle. It was definitely a different time.
Hard to have that loyalty these days when so many brands shift their models.
Though I’ve met many newcomers to the country, and their first car is an Elantra/Jetta/Corolla and their next car is the SUV of the exact same brand (Tucson or SantaFe/Tiguan/Rav4)
I actually wrote something about that originally, but edited it for brevity (I actually do that once in a while). Yeah, that happened to me. I prefer a type of a car to a brand and my types are not what most cars being made are (or ever were, but there were at least a lot more options from many companies than today’s selection of matryoshka doll CUVs). It makes sense if people are still loyal if they’ve had a good experience with the brand and, if they don’t care much about driving, the lack of generally lower utility body styles isn’t an issue.
I’m 54. I have said here often how the over-proliferation of unnecessary “tech” in today’s cars actually actively makes me NOT WANT a new car.
If your dad is 54 or older, try this approach with him and see what he says. “Dad, do you want a car that does what you tell it to, or do you want a car that does what it thinks is right regardless of what you want to do? Because there is not any new model available anywhere from any manufacturer that won’t tell you how to drive these days. You’d rather do your own driving, right? You don’t want to be spied on by your own car, do you? You don’t want some eastern European hacker to be able to rob you from halfway around the globe, do you? Welp – maybe take a look at the used lot with new eyes and see if it looks any different.”
My dad is 80 and my father-in-law is 82.
My parent’s last new car purchase was a 2024 RAV4 hybrid. They both like the car. My mom really likes the large screen and carplay integration. My dad doesn’t but he hates phones and computers with a passion. He would use a flip phone if the last one he purchased didn’t crap out after 2 months. Today he uses my mom’s old iPhone but I’ve removed or hidden all the apps except for the phone, message, and calculator. My dad loves the adaptive cruise control but hates the lane keep feature. (He hates lane keep because he drives almost directly on the center line so lane keep continually tries to move him back into the center of the lane)
My in-law’s last car purchase was a 2025 Escape. (Got the year wrong above as now I remember they bought it in response to Trump’s liberation day tariffs because they expected his tariffs to drive up car prices)
Same mix. My mother-in-law loves the screen and android auto. My father-in-law hates the screen but he does in fact still use a flip phone. My in-laws have all the safety features enabled and my mother-in-law has said the auto-brake feature has engaged several times and kept her from hitting someone.
All in all I personally think that all 4 of them are on the line or past the point of when they should hang up the keys but none of them will because they live in an area where a personal car is the only option for transport. They have stopped driving after dark.
I look at these and think how much they sucked in corners and stopping.
Yes.
But so did much of that era.
yes nearly everything but a few and that is why I have no interest. It was not about this specific car but all the rest also.
Funny – I look at these, and I think of what Car And Driver said in their review of the new 1970 Trans Am: “A hard muscled, lightning-reflexed commando of a car, the like of which doesn’t exist anywhere in the world, even for twice the price.”
But then, what did they know anyway.
In 1970 Car and Driver knew the world as it existed in 1970. For 1970 the Trans Am may have had lightning reflexes.
Fast forward to 2026 and nobody is going to praise 1970 muscle car handling nor think a 13 second 1/4 mile is fast.
Well, they also reviewed the Corvette and the DeTomaso Mangusta that year, and had reviewed the then-available Porsche 911S and a prior model of the Lamborghini Miura.
It was a great car that acquitted itself well against other cars some would call greater for the time. Whether faster or better handling cars have come out since is irrelevant.
No, the fact that better cars are available than what was sold in 1970 is not irrelevant in 2026. 4jim said he has no interest in cars from the 70’s because they handle poorly. I feel the same.
The cars that I thought were great when I was a kid in the 80’s and early 90’s are objectively crap today. And that is OK. We can put down the rose colored glasses and acknowledge progress. Nostalgia doesn’t change facts and time and technology marches on.
I had a ’77 TA (I know, I know…).That car would easily outstop pretty much anything but a vette at the stoplight drags, and it went around corners way better than most.
GM’s F bodies handled really well for the era. I wouldn’t describe them as sucking in corners at all. And yes, I drove a few of them when they were new, including a WS6 Trans Am.
If anything, when properly optioned, Pontiac had the best handling American cars, aside from the Corvettes of the era.
A big thing back then was the tires. Radial tires were not common when this car was designed and the suspension was setup for the hard riding bias ply tires. When you drive one today with radials, it’s all squishy and soft, when it would have been different on the Bias plys it originally came on.
There used to be (still is?) a thing called “Pure Stock” for musclecars. SD-455s were a cheat code there. The issue is that all muscle cars of that era have more power than traction, even with much more modern tires, on the original wheel sizes. Somehow, the Firebirds hook up dramatically better and pull multiple car lengths before the emissions and lower compression limit their top end speed. So Pontiac did some significant suspension tuning with these things to get them to launch in a straight line. As for dancing? Not going to happen on biasply tires.
I really love Pontiac’s “dark era” of advertisements from the 70’s that the last photo is from. They are incredibly atmospheric in their vibes.
I know this is a weird complaint, but I wish the engine looked special.
Put some fancy valve covers on it or something. I remember being around muscle car guys who just opened their hoods on lumps of iron looking like this and expecting immediate recognition, getting a bit grumpy if I didn’t immediately know what it was / why it was special.
I could look at the exhaust port spacing and tell the difference between a chevy big block or small block, but unmarked slightly rusted stamped valve covers all look the same to me.
That’s about all you could do to this era’s cloned iron block OHV engines. They were all much closer to each other in design and appearance than different and unique. One might even say, mechanically boring.
They could dress it up a bit. That four barrel carb / intake combo that Ford made had some raised machined lettering.
It doesn’t need to be chrome and polished, but a little something special would be nice.
But it does look special. The shaker says “SD-455” on it.
It says absolutely everything.
That would be cheating. These lawn chair warriors want you to ID the engine without looking at any text.
90s cruise nights were brutal.
The lack of variety in domestics is one of the reasons why I found foreign cars so much more interesting and preferred going to those shows instead.
Didn’t matter much. If there’s a place to park, some boomer will plant his POW-MIA ass in a lawn chair at the trunk of his 196-7x whateverthefuck and look for a chance to shit on you for not knowing absolutely everything about the car.
They treated you like a private that had not done their homework and needed to be harshly corrected for it. If those miserable fuckers could have made you do pushups, they would have. I may have self-exposed to car shows at an early age, but my main attitude towards boomers is ‘FU and the uninteresting muscle car you rode in on.’
In high school, I used to show up to a local cruise night with my ’84 Subaru wagon art car. The few with senses of humor loved it, but the rest looked at me like I ripped a fart in church for interrupting the sacred sea of tri-fives and paint-by-number deuces all powered by Chevy 350s they claimed to have more power than they did for them to drive 20 under the speed limit, anyway. Those creepy kid dolls they set up must have been hiding their faces in shame.
The derision in your comment tracks pretty close to your complaint about their attitude. I just assume, as veterans, they probably earned their crankiness, thank them for their service and move on.
I don’t know if any of you ever took Hemmings Muscle Machines, but it used to have a back-page editorial written by a rotating list of staff writers. One writer, of roughly “boomer” age himself (a guess), wrote an editorial complaining about exactly this attitude at car shows. He nicknamed such know-it-alls as self-appointed “Masters Of The Marque,” people who like to think they know way more than you do about a particular car or a particular brand, who either actually do and are jerks about it, or worse, actually don’t and are still jerks about it.
Edit: found the article, and I forgot what a great title it actually had: “Masterly, malignant misanthropes.” LOL
https://www.hemmings.com/stories/masterly-malignant-misanthropes/
I ended up in an S12 200SX after crashing my third 3rd gen F Body and it changed my automotive life.
At least they didn’t bolt a giant piece of molded plastic on top of the engine and pretend that’s what the engine looks like.
I agree with that. My favorite is when the engine cover seems longitudinal (latitudinal? GD, I wish all cars were just RWD or RWD-based AWD) on a FWD car.
Semon Emil “Bunkie” Knudsen
It’s not a wonder he preferred to go by his nickname.
Emissions cheating: a time honored American tradition!
And time marches on is right. A family EV crossover would destroy this in a quarter mile. That said, this would be getting lots more attention anywhere it went.
Well… maybe by now. But the 1973 SD-455 sent out for press testing (which, admittedly, was quite “breathed on”) ran the 1320 in 13.54 seconds. The next American production model to equal or beat that time would take another 14 years: The 1987 Buick Grand National GNX. And it would be another 25 years after that before it would be bested by a so-called “family EV,” the 2012 Tesla Model S Performance… if you had 92 grand in 2012 dollars.
It just simply ain’t that simple.
Also: from 1973-1987, I was age 1-15. Since both I and my love of cars developed directly concurrently with “The Malaise Era,” I, like so many of my peers, came of age as a budding Autopian hardwired to look to the past for actual fast cars. This accomplishment absolutely cannot be overstated, in its proper context. This is also why even now, 40 years into the second American horsepower renaissance, there is still a part of me that wants to think cars used to be faster – at least, until I snap out of it and remind myself that you can buy 700 horsepower off the showroom floor today.
They certainly felt faster and, for me, that’s what matters a lot more, especially now that the numbers are so ridiculous and unusable.
A lot of the feel of power from that era was the explosion of sound from the back when you touched the throttle too hard. All “powerful” cars were massively undertired back then and the screams of dying tires made them feel a lot more powerful than they actually were.
Right, and they were a lot more fun while being less dangerous to use in that the speeds didn’t demand as perfect and as quick reactions and the low limits gave plenty of communication and more opportunity to be familiar with its limits while having none of the electronic interventions that may help or hinder recovery in unpredictable ways. Modern cars have too much tire, too much power, too much insulation, and too much electronic nannery while living in a world with far more road users with worse skills.
My first car could pull maybe 0.7 g on a good day. Around 0.5g the tires started howling like upset Huskies and screaming like cats having a war around 0.6g. I had tons of warning that I was pushing it, as did everyone in the neighborhood. Being a teenager and stupid, I did overcook turns and ended up out of control but at speeds that a snail on redbull had a chance to outrun me.
My current car is nothing special and can go to likely 0.8g. Around 0.7, there is a slight noise from the inside rear wheel as it starts to chirp a bit because it’s lifting a bit in mid turn. I am smart enough to not push it to the limit, but if I did, I know it would just suddenly bite me, instead of warn everyone within 3 blocks that I was being stupid.
That’s another reason I miss sidewalls. That and the ride. The smaller wheels is a big reason why I got the base GR86 (though I am a cheapskate, it also happens that my preferences align with that sensibility as I didn’t want the other stuff that came with the higher trim).
There were other ICE American cars that matched or beat that GNX by the mid-90s.
The current vehicle landscape makes it hard to remember that 13 seconds was pretty special. These days it’s the hot version of a compact sedan or the AWD version of almost any EV even if it has no other sportiness to it.
My formative car years were in the mid-90’s and I seem to remember that a 14 second time was considered pretty average, and ‘breaking into the 13s’ was when you finally had a quick car.
And 8 years ago I was able to walk into a Chevy dealer and plunk down enough cash to walk out with a relatively inexpensive Cramro that would run mid-12s off the lot.
Ha. Precisely my point: “breaking into the 13s” was “finally a quick car” in 1968 too, and looking like a thing of the past by 1973. The 90s picked up where the last SD-455 left off in 1974 – in the 13s.