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How many "400" V8s has GM built over the years?

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AFAIK, Chevy built two - one smallblock and one bigblock.

How many each from Pontiac, Buick, and Olds?

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Shoot I never heard of Buick or Olds 400s, only Pontiac. Pontiac's was the most famous GM 400 CI V8 for good reason, imo.

And a Chevy big block 400? I must be having a brain fart, I never heard of it. I know 396s were bored out to 402 later on, but I never heard of a 400 rat.

I think there was a Buick 401 and an Olds 403, the latter of which was slipped into some Can Ams and Trans Ams...

Edited by ocnblu

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The big block 400 was actually a detuned version of the 402 which itself was marketed as a 396. So despite the "400" badges the engine actually displaced 402 cubic inches.

Goofy, but true.

I believe it was engine code LS3, but I'd have to doublecheck.

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Shoot I never heard of Buick or Olds 400s, only Pontiac. Pontiac's was the most famous GM 400 CI V8 for good reason, imo.

And a Chevy big block 400? I must be having a brain fart, I never heard of it. I know 396s were bored out to 402 later on, but I never heard of a 400 rat.

I think there was a Buick 401 and an Olds 403, the latter of which was slipped into some Can Ams and Trans Ams...

As far as the Buick 400, it was used in the GS400 from '67-69 after the Nailhead was retired. The Olds 400 was around '65-69, was the top engine in the 442 amongst other applications.

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Pontiac ~ 400 : '67-79

Of note: PMD 400RA: "LS1", SD455: "LS2", 455HO: "LS5"

Buick ~ had the 401 : '59-69. Buick marketed it as a '400' name-wise when the 'Skylark Gran Sport' of '65-66 was renamed the 'GS400' from '66-69. Tho the bore & stroke were the same, the GS had to be called a '400' to get by the Corporate edict that no intermediates could have over 400 CI. Whether or not this is a snapshot of the autonomy Divisions had vs. corporate oversight this late or not, is open to conjecture... but seems logical IMO.

Olds ~ got a 400 with the '67 442. I believe it only lasted thr '69, when the 442 went to the 455.

Chevy ~ the 400 and the 402 came out for '70.

350 : 4.000 x 3.48

396 : 4.094 x 3.76

400 : 4.125 x 3.75

402 : 4.126 x 3.76

I see the 402 being an overbore on the 396... I just don't see where the 400 is a typical enlargement of the 350. Different crank? Not that up on the Chevys- Camino- you prolly kno better than I.

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Buick ~ had the 401 : '59-69. Buick marketed it as a '400' name-wise when the 'Skylark Gran Sport' of '65-66 was renamed the 'GS400' from '66-69. Tho the bore & stroke were the same, the GS had to be called a '400' to get by the Corporate edict that no intermediates could have over 400 CI. Whether or not this is a snapshot of the autonomy Divisions had vs. corporate oversight this late or not, is open to conjecture... but seems logical IMO.

Buick had 2 different 400s, though, right? The Nailhead 401 '400' up thru '66 and a 400 from the '67-69 that was of a different engine family (i.e. the Nailhead replacemen that had a 425 and later 455).

Olds ~ got a 400 with the '67 442. I believe it only lasted thr '69, when the 442 went to the 455.\

'65 according to what I read.

Edited by Cubical-aka-Moltar

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Balthy, the Chevy smallblock 400 is an odd bird. Even the casting is different, the two inner cylinders on both sides are siamesed. It was once prized as a drag motor, but had heat problems that could make the thin walls of the casting crack.

No, it isn't just an enlarged bore of the 350.

Aftermarket companies were casting smallblock 400s that fixed its issues and made great performance engines (usually displacing 406 cubic inches).

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Some quick research, and the postings here, indicate that the 400 count is six total.

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Olds ~ got a 400 with the '67 442. I believe it only lasted thr '69, when the 442 went to the 455.

'65 according to what I read.

Of course that's right; in '65 442 stood for '400, 4bbl, 2 (dual) exhaust'.

Buick ~ had the 401 : '59-69. Buick marketed it as a '400' name-wise when the 'Skylark Gran Sport' of '65-66 was renamed the 'GS400' from '66-69. Tho the bore & stroke were the same, the GS had to be called a '400' to get by the Corporate edict that no intermediates could have over 400 CI. Whether or not this is a snapshot of the autonomy Divisions had vs. corporate oversight this late or not, is open to conjecture... but seems logical IMO.

Buick had 2 different 400s, though, right? The Nailhead 401 '400' up thru '66 and a 400 from the '67-69 that was of a different engine family (i.e. the Nailhead replacemen that had a 425 and later 455).

The GS400 was a 401, so technically it wasn't a '400'- just marketed that way. But including that marketing, you're correct again.

WRT the Chevy 400, just seems as if it wasn't necessary. Chevy could've had a stouter, more mod-friendly package had they offered their own 383 (350 stroker).

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WRT the Chevy 400, just seems as if it wasn't necessary. Chevy could've had a stouter, more mod-friendly package had they offered their own 383 (350 stroker).

Very true. I can't really explain why that motor ever existed.

They should have just borrowed the 455 from Pontiac.

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Wait- why would they borrow

1. a Pontiac motor, especially a 455 when

2. they had their own 454?

Edited by balthazar

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A good thread, thanks for the Four Hundred eleven. I had forgotten about the Skylark GS400 (even though technically it was not), and never knew Olds had a 400 CI (I always heard it the way Drew did, 4bbl, 4 speed, dual exhaust, at least until the awesome 4 cylinder, 4 valves per cylinder, dual cam N-body 4-4-2) :smilewide:

Edited by ocnblu

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Wait- why would they borrow

1. a Pontiac motor, especially a 455 when

2. they had their own 454?

Well, because the 455 weighed lots less than the 454 and would have worked in a smallblock/big displacement application better than the 400.

I suggested it sort of tongue-in-cheek, but it would have made a better package.

Maybe I should have suggested that they borrow the Pontiac 400 instead.

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^ Gotcha.

I don't have weights handy for those 2, but supposedly a Pontiac 421 weighed 685 (full dress) and a Chevy 427 weighed 695. Pontiac 455 may have had a tiny bit less beef in the block- not sure.

It's just weird that the brand new '71 Chevy 400 came out... and it came primarily in the MC & F/S... the 402 came out the next year. If they were trying to shoehorn the 402 into the Vega or something, I could see the 400 SB, beyond that I don't get why it was.

But you know the big cars never shared engines then (tho it was short spin into the future before they would).

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402 was late '69 into '70 (though still called the 396)

What's weird is that I've seen the 402 (badged as a 400) used in the A-bodies (non-SS cars) and the 400 smallblock used in the Impala/Caprice.

None of it makes much sense to me.

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402 was late '69 into '70 (though still called the 396)

What's weird is that I've seen the 402 (badged as a 400) used in the A-bodies (non-SS cars) and the 400 smallblock used in the Impala/Caprice.

None of it makes much sense to me.

Interesting..the way it's explained on Wikipedia is that the 402 was badged as a 396 in A-bodies (never seen a Chevelle with a 400 badge) and as a Turbo Jet 400 in the B-bodies (apparently both the 400 small block and 402 were available in B-bodies in the '70s).

But apparently, the 402 was never advertised or badged on a car as a 402 for unknown reasons.

On the other hand, I have seen full size ('72, 73 Impalas) with 400 fendr badges..don't know *which* 400 those designated, though..

Edited by Cubical-aka-Moltar

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Yea- I never have committed to memory which year the Chevelle SS396 is first a SS402.

I believe Chevy stuck with "396" because of the recognition factor, esp in the Chevelle SS.

Why they did the same with the F/S cars is unknown to me.

My buddy has a '71 MC with a 402, the original air cleaner says "400".

Edited by balthazar

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Yup, it was name recognition.

I've seen Chevelle wagons and El Caminos with "400" badges, and the 402 under the hood.

Can't say I've ever seen a sedan or coupe though.

I definitelyhave not seen any Chevelle, wagon, or EC with the 400 smallblock.

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IIRC, I have 6 400s... 3 Pontiac 400s still in the cars, 2 Pontiac 400s out of the car and 1 Chevy 400 SB in the '76 Blazer.

When I got the Blazer, my father was pissed. He hated the 400 SBC... I figured it can't be too bad if it had survived 25 years... and swapping in a different motor (like a 350 with the 400's crank) is no big deal.

The engine has been as fine as can be expected for a somewhat worn out example. My problems started when I put a brand new distributor in it.

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I've never had a Pontiac 400, but I've had (8) 389s.

Best thing about the 400s is their easy to find and you can drop a new 455 crank forging that already has the smaller mains. That way you get the advantages of the 455 without the oiling issues some have with the large mains.

IIRC, you can do the same with the 389, but you get a 428 or something. I'd have to check the math.

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Yeah, the Buick nailhead 401 was retired after '66; for '67, the new Buick "big block" appeared--also came in a 430 CID version that year and, starting in '70, a 455 CID version.

I remember looking at a '72 Impala with a "400" emblem on the front fender and under the hood lurked a 402 (bored 396).

Olds had two 400s: the shorter-stroke 1965 - '67 version and then the '68-'69 version that had the 455's LONG 4.25" stroke (and a 3.875" bore--talk about an undersquare V8!).

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