Home » Engines Of Varying Displacement: 1981 Cadillac Seville vs 2006 Chrysler 300C

Engines Of Varying Displacement: 1981 Cadillac Seville vs 2006 Chrysler 300C

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On today’s Shitbox Showdown, we’re taking a look at two luxury sedans with V8s that are capable of acting like much smaller engines. One was an unmitigated disaster, and the other, well, the jury’s still out on. But before we pop the hood on those, let’s see how yesterday’s lawn ornaments did:

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Huh. I am surprised, and I’m not sure I agree. The Rodeo would make a fine beater, if you could hop in and drive it away, even if it needed some work. But the idea of resurrecting a non-running early-90s SUV has about as much appeal to me as a day-old Big Mac. I’ll take the Newport, keep the patina, and drop in an engine from a newer Dodge truck.

We all know what we love about V8 engines: the sound, the smoothness, the rush of torque that pushes you back in the seat when you step on the go-pedal. And we all know what their worst attribute is: fuel consumption. But what if you could have a V8 that was only a V8 when it needed to be, and ran on fewer cylinders under light loads to save fuel? Sounds like the best of both worlds, right? Well, GM engineers thought so, twice, and the second time were joined by Chrysler. It’s rarely the case that the sequel is better than the original, but this is definitely one of those cases. But let’s give them both a fair shake, and see what you think.

1981 Cadillac Seville – $2,900

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Engine/drivetrain: 6.o liter overhead valve V8, three-speed automatic, FWD

Location: Bakersfield, CA

Odometer reading: 19,500 miles

Runs/drives? Starts, not drivable

Cadillac’s midsized Seville was completely redesigned for 1980, from an unremarkable four-door sedan based on a Chevy Nova to a bold, dramatic reimagining of a 1930s luxury car. Bill Mitchell’s design featured a “bustleback” trunk and a long hood meant to evoke Cadillac’s glory days of fifty years earlier. But I remember my grandpa giving its design a less flattering appraisal upon first seeing one: “Looks like someone ran over its ass with a steamroller.”

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Powering this bold new styling were bold new engines: Oldsmobile’s utterly miserable 350 cubic inch diesel V8, and for one year only, in 1981, this abject failure: the 368 cubic inch V8-6-4. Throttle body fuel injected and computer controlled, this engine could run on four, six, or all eight cylinders, depending on the throttle input. But the system worked too slowly to keep up with demands, and drivability was appalling. Most V8-6-4s were converted to run in V8 mode all the time, which could apparently be done by cutting one wire, but then you were left with a huge, thirsty V8 that still had no power to speak of. The gutless Buick V6, available as a credit option, might have actually made sense by comparison.

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This Seville, with fewer than 20,000 miles on the odometer, apparently has the cylinder-deactivation system intact. The seller says it starts and runs, but can’t be driven, but I wonder if it’s actually just fine (or as fine as these ever got) and they just don’t know what to expect of it. The common complaint of these was a lag when switching back to eight-cylinder operation, making the car sluggish and feel like it’s misfiring. Of course, there may be something more serious wrong with it.

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Wonky engine aside, the rest of it looks like you’d expect from a malaise-era Cadillac with almost no miles on it: clean, but sloppy-looking. Build quality was merely a suggestion in the early Reagan years, but that was hardly a problem unique to Cadillac. These bustlebacks were never my cup of tea, but I know they have their fans, and this one is about as clean as I’ve seen in a long time. You could bolt in any Buick-Olds-Pontiac-Cadillac bellhousing pattern V8, leave the “MPG Sentinel” in the dash as a conversation piece, and cruise around in… well, I guess you could call it style.

2006 Chrysler 300C – $4,000

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Engine/drivetrain: 5.7 liter overhead valve V8, five-speed automatic, RWD

Location: Lake Oswego, OR

Odometer reading: 161,000 miles

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Runs/drives? Just fine

This car, I’m a lot more familiar with. I drive a newer version of it every day, same color, in fact. Chrysler’s LX platform is arguably the best thing to come out of the ill-fated “merger of equals” with Daimler. A large, comfortable rear-wheel-drive sedan was just what the Mopar faithful needed to forget the “nothing but K-cars” era. And the fact that it has lasted for nineteen model years and will be sorely missed when it goes away only drives home the fact that this is one car that Chrysler, in its many guises, got right. The Hemi V8 is, of course, a big part of that success.

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This 5.7 liter version of the V8 with the famous name features its own cylinder-deactivation system. Chrysler skips the six-cylinder mode and goes straight from eight cylinders to four, deactivating cylinders 1, 4, 6, and 7 at steady speeds. Advances in computer technology have eliminated the lag, and the Chrysler system works by collapsing the hydraulic lifters instead of disconnecting rocker arms, making for a simpler mechanical system. It’s generally a reliable and durable system, but there are reports of failures, usually caused by neglecting oil changes or using the wrong viscosity oil, resulting in bent pushrods and wiped cam lobes. You can turn the system off by putting the transmission in “Sport” mode, but it reverts to normal when you turn off the ignition. A more permanent disabling involves replacing the camshaft, lifters, and some other things.

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This 300 runs great, and has had some recent service including a fluid change to its Mercedes-sourced five-speed automatic transmission. Everything works except the display screen on the infotainment system; fortunately there are buttons and knobs for everything, but setting radio stations might be a bit of a crapshoot.

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Otherwise, it looks like it’s in good condition, and a hell of a lot of car for four grand, actually. And the fact that this one is in such good shape after 161,000 miles makes me optimistic about the future of mine. These are a great way to enjoy a Hemi without the boy-racer stigma surrounding the Dodge Charger and Challenger.

V8 engines have been a cherished part of the automotive landscape for more than a century now, but they’ve never been the most thrifty option. It’s a bit irritating that, now towards the end of their run, the multiple-displacement method of making them more fuel efficient has actually started to work, but better late than never, I suppose. You can either take the museum-piece 1980s version try to make it work, or just go for the ready-made 2000s version. What’ll it be?

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(Image credits: Craigslist sellers)

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Ranwhenparked
Ranwhenparked
11 months ago

In either case, you will be best advised to disable the deactivation system, although, at 161,000 miles, any neglect related damage on the Chrysler is probably already done and you’d might as well run to failure.

Bizarrely, the V8-6-4 is probably the best engine to have in the Seville, since it turns into a totally normal, reliable V8 just by disconnecting the system. The Olds diesel alternative and the later HT4100 can not be corrected so easily. The Buick V6 is something that seemed to exist in them more in theory, I’ve actually never come across an Eldorado or Seville of this era that had one, the take rate had to be exceedingly low to the point where you just shouldn’t really expect to ever find one

Brooks Fancher
Brooks Fancher
11 months ago
Reply to  Ranwhenparked

Pops bought one of the early Oldsmobiles with that diesel, gawd that thing was POS!

StillNotATony
StillNotATony
11 months ago

Is this a test? This feels like a test of some sort. Are you trying to find the real weirdos among us or what? Because it would take a real weirdo or someone with a very specific fetish to pick the Caddy over the Chrysler.

This is only a test.

I’m not a weirdo. Chrysler.

Trust Doesn't Rust
Trust Doesn't Rust
11 months ago
Reply to  StillNotATony

I’m a real weirdo and I still picked the Chrysler. Aside from the works-in-theory-but-not-in-practice styling, the Cadillac has nothing going for it, especially when compared to the Chrysler. And I’m not fan of the Chrysler.

Nic Periton
Nic Periton
11 months ago

I will take the Caddy, swap in a carburetted Jaguar V12 and voila, improved reliability and better fuel economy.

Rusty S Trusty
Rusty S Trusty
11 months ago
Reply to  Nic Periton

I know you’re joking but you aren’t wrong

NewBalanceExtraWide
NewBalanceExtraWide
11 months ago

I genuinely like the hunchback with no irony, but I also like the 300 without irony. The newer one gets my vote, and I have questionable taste in automotive styling.

Nlpnt
Nlpnt
11 months ago

Ugh. You’re killing me. I like posting these in an evening discussion forum but it’s are Mopar-guy heavy so it only works if the number of Chrysler products is zero or two.

The Chrysler runs and drives and is actually fast, but in that dated-but-not-yet-classic phase and will be for at least another decade. The Caddy is something whose looks I’m starting to appreciate as pure automotive sculpture even if putting it into production was a sorry mistake on GM’s part and kicked off Cadillac’s Lost Decade of geriatric styling and shit engines that they’ve never really recovered one. So yeah, I’m with the Mopar guys on this one.

Squirrelmaster
Squirrelmaster
11 months ago

Had a friend back in the 90s with a nearly identical Seville (same funky pink/tan color as well), and what a horrendous pile of crap it was. The V8-6-4 was a turd, even with the variable displacement disabled, strapped to an even more garbage transmission (THM-325).

Even with the suspiciously low price for the 300C, which would normally have me calling shenanigans on it, there is no universe where the Seville would beat it.

Chronometric
Chronometric
11 months ago
DDayJ
DDayJ
11 months ago

Both. Caddy for Radwood and the Chrysler to get around in.

MaximillianMeen
MaximillianMeen
11 months ago
Reply to  DDayJ

The Chrysler has a tow bar. You’ll need it to haul the Caddy to Radwood.

Justin Short
Justin Short
11 months ago

Caddy for the nostalgia and an engine swap

Bomber
Bomber
11 months ago

Hemi 300C for 4K and it runs? What Caddy?

Jonathan Green
Jonathan Green
11 months ago

Cadillac by a mile. Look, you can find plenty of 300C Chryslers out there, and even get a new one. We had one when they first came out, and it was fantastic. Fast, roomy, but a pig on gas and in the snow.

But the Caddy was also a statement. That car was the future without the function. GM got ahead of itself technologically, but it was right about everything else.

I guess what I’m saying is screw you guys, the Cadillac is cool.

Geoff Buchholz
Geoff Buchholz
11 months ago

More than 43 years after the premiere of the 1980 Seville, I can still remember David E’s one-line “counterpoint” in the C/D road test: “If the Seville was the answer, I obviously misunderstood the question.” All-in on the 300, please.

XLEJim700
XLEJim700
11 months ago

Shooting fer the PentaStar.

Soso Tsundere
Soso Tsundere
11 months ago

That 300C is way too good of a deal to be on the showdown! Maybe if they had a disclaimer that it was the scene of a murder… but even then it looks cleaned up and is far too good of a deal for this used car climate.

Canopysaurus
Canopysaurus
11 months ago

Looks like the barber of Seville took a bit too much off the back. Ugh, no thanks. Mundane Chrysler product wins the day.

ToyotaTaxPayer
ToyotaTaxPayer
11 months ago

I was a always surprised so many old folks wanted to be pimps driving the 300s. Im not a Chrysler fan but that caddy was junk, is junk and will always be junk on top of being fugly

Ranwhenparked
Ranwhenparked
11 months ago
Reply to  ToyotaTaxPayer

There is a very strong overlap between elderly white men and pimps when it comes to automotive tastes

Man With A Reliable Jeep
Man With A Reliable Jeep
11 months ago
Reply to  Ranwhenparked

Perhaps there’s an aspirational aspect as well…

Pupmeow
Pupmeow
11 months ago
Reply to  Ranwhenparked

Ha! My grandpa (an elderly white man) drove a purple, lowered Chevy S10 for most of my childhood. It had flame decals and a personalized license plate.

Imagine my surprise when I moved out of my small hometown and discovered that he was not the target demographic for that car.

Cheap Bastard
Cheap Bastard
11 months ago
Reply to  Ranwhenparked

How do you think he met grandma?

Angrycat Meowmeow
Angrycat Meowmeow
11 months ago

That 300 is way too clean to be $4k. Something ain’t right there. Even with my doubts, there’s still no way I’m voting for the butt ugly Cadi.

A. Barth
A. Barth
11 months ago

The seller included a screenshot of the KBB valuation: https://images.craigslist.org/01010_6Xsa6afsW34_0eF0lX_1200x900.jpg

Apparently the appropriate private party sale value is ~$4200. I suspect the high mileage contributes to the low price.

Nsane In The MembraNe
Nsane In The MembraNe
11 months ago

Easy dub for the 300C. I’ve been saying for a long time that enthusiasts are sleeping on the 300. They offer a true luxobarge experience with a V8 and RWD for pennies on the dollar. There are tons of them out there as well and the more recent ones are well sorted at this point late in the model’s run.

I haven’t personally driven anything with the 5.7 but it’s ubiquitous at this point and pretty universally liked. It’s also very under stressed from the factory and takes to modifications really well. The general consensus in the Mopar community is that if you want to build a Charger or Challenger yourself the 345 is the better choice than the 392.

Anyway, I’m hoping that the current 300C depreciates a bit because I’d love to consider it in a couple years. Even the regular 300S with the Hemi is a great buy but it’s so hard to find one that’s lived a normal life. Most wind up in rental fleets where they get the snot beat out of them and receive 0 preventative maintenance. It’s best to stay patient and wait for a true “old lady” one to pop up.

Timothy Arnold
Timothy Arnold
11 months ago

That old Caddy 4-6-8 system may have been ahead of it’s time, but it was a disaster, so no thank you.

Man With A Reliable Jeep
Man With A Reliable Jeep
11 months ago
Reply to  Timothy Arnold

I find it funny that GM still can’t quite get the hang of cylinder deactivation without destroying the engine, even though the technology has been out for decades. Granted, at least they’re not alone anymore in that regard.

V10omous
V10omous
11 months ago

You can turn the system off by putting the transmission in “Sport” mode, 

That’s all I needed to hear.

Mike S
Mike S
11 months ago
Reply to  V10omous

You really don’t need to, I have two 5.7L Hemis with cylinder deactivation, 200,000 miles between them, and they’re both quite seamless, I assure you. Usually the only way I can tell if I’m operating on only 4 is the tiny “eco” text that lights up by the speedo. Great engines 🙂

Rollin Hand
Rollin Hand
11 months ago

Gotta go Hemi here. The Caddy could be fun with an engine swap (seriously, imagine rolling up to a Cars & Coffee with an LS swapped Seville with “SEVILAN” personalized plates), but the Chrysler is fun now, at least until a lifter goes.

And the screen should be easily replaceable.

Ranwhenparked
Ranwhenparked
11 months ago
Reply to  Rollin Hand

I always wondered if you could put a later Cadillac 4.9 or a supercharged Buick 3.8 in one

Thomas Metcalf
Thomas Metcalf
11 months ago

I wouldn’t take the Caddy if it was free.

Brandon Forbes
Brandon Forbes
11 months ago

Wow 100% for the 300. Makes sense, I don’t even like them and can’t justify the Cadillac. One runs and drives, one doesn’t and sucks even when it does. Not contest today, clearly by the one sided voting so far. Surely some crazies will come along and vote for the Caddy, but it’s not worth it.

Man With A Reliable Jeep
Man With A Reliable Jeep
11 months ago

The Hemi Chrysler 300C wins all day, every day, even Sunday, and on an eighth day, Funday, because the awful V8-6-4 in that Cadillac is not fit for human consumption.

Brandon Forbes
Brandon Forbes
11 months ago

I would hope not! It consumes gas, not people! I don’t want it as is, but I certainly wouldn’t want it if it ran off human body parts!

Man With A Reliable Jeep
Man With A Reliable Jeep
11 months ago
Reply to  Brandon Forbes

Heh. That was a reference to Sergio Marchionne’s (in)famous paraphrased quote about the Jeep Commander being “unfit for human consumption.”

Brandon Forbes
Brandon Forbes
11 months ago

Fair, I just saw an opportunity to take advantage of the vagueness of the English language and twist it into something dark. So I ran with it.

SlowCarFast
SlowCarFast
11 months ago
Reply to  Brandon Forbes

“It’s people! Biofuel is made out of PEOPLE!!!!”
(Are you old-enough to get the movie reference?)

Brandon Forbes
Brandon Forbes
11 months ago
Reply to  SlowCarFast

haha I am not, but a quick google search led me to it. Sounds like the Autopian now needs to make a movie that crosses Soylent Green and Death Race!

SlowCarFast
SlowCarFast
11 months ago
Reply to  SlowCarFast

Edit: I just looked it up, that 1973 movie took place in a 2022 dystopia. Not yet, movie. Give us 20 more years)

TurboCruiser
TurboCruiser
11 months ago

300 no brainer

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