Will a 400 small block w/ 400 turbo trans from a '72 Pontiac Grand Prix fit right into an '88 Firebird?

Question

This IS a small block 400. Fact.

Answer 1

The Pontiac 400 is not a Small Block it's a Big Block. As far as installing it in a 1988 Firebird it'll probably take a lot hard work and money.

Answer 2

If it's an original 1972 Grand Prix 400ci engine, it's not a Chevy block, it's a Pontiac block. They were physically larger than a Chevy small block 400. All Pontiac blocks were physically the same size regardless of the cubic inch displacement. The differences were the bore and stroke but physically they were all the same size from a 287 to a 455. They were larger than a Chevy small block but smaller than Chevy big block.

Your 1988 firebird would be built with a Chevrolet small block based V8 which as I stated is physically smaller than the older Pontiac engine. It would not be a direct bolt in job. It would require a lot of modification. Can it be done ? Of course it can with the right mods.

You stated that yours has a small block 400 (assuming you meant the Gran Prix) so it may not be the original engine and may have already been swapped. Pontiac did not start using Chevy engines until 1977.

BTW, in 1972 the bolt pattern for transmissions was the same for Buick , Olds, Pontiac, and Cadillac but Chevrolets was different .

Answer 3

If that's a 400 small block, then yes, it'll fit just fine.  But the fact that you took it out of a 72 GP is irrelavant, because, as you know, 400 small blocks weren't available in any Grand Prix, ever.

So it's just a small block chevrolet out of /something/ we don't know what.

Plus, if you insist it's a small block, and you know the 1988 also is also a small block Chevy, you've kind of transformed this into a stupid question.  It's a bolt in, right?  If you insist they're both small block Chevies.

Answer 4

the 400 is a small block chevy motor, basically a 350 with bigger bore, stroke, and main journal diameter. all of the original intake parts(TPI), headers, distributor. from this car will fit on the engine and it will work fine, it just takes the know how on how to put it back in with all the right connections. I own an 87' trans am and ive already had 2 different motors i have put in them. but i am pretty sure you will need a new shifter for the TH400 transmission