whats the difference b/t a chevy 400 small block and a pontiac 400 small block. are they like the gm ls1 w/ the ablility to be changed b/t both chevy and pontiac w/ no problems. are the engine mounts the same. i know all the parts are but will a pontiac 400 small block fit into my truck just as easy as the sbc400. and will it bolt right up to my tranny?

 

Well, for one a 400 Pontiac is not a small block. Its a bigblock and is VERY difrent then a SB 400 Chevy. There are no interchange able parts between the two. You can interchange whole motor in second gen camaros and firebirds, but that's about it. I'd stick with a Chevy in your truck, much cheaper to build and a much better aftermarket.

The very first motor I ever built was a 400 Pontiac. I pored a ton of money into it, rebuilding it a couple of time (it was my first and I screwed a couple of things up ). I put it in a 80 Buick Regal (custom motor mounts and moded headers) I though it was fast (I was 17 lol) but it only ever ran low 17's

 

engine mounts are different than chevy and they also differ with years. pontiac uses a different tranny mount than chevy although an inexpensive adapter is available from trans-dapt. pontiac has a decent sized aftermarket with blocks available in aluminum and several companies making aftermarket heads. like anything else they can fast with the right amount of $$$

 

i sure as hell thought the pontiac 400 was a small block...damn!!

 

Pontiac actually doesn't go by big block or small block. From a 301 to a 455, they're all the same size and look nearly identical on the outside.

 

chevy has small block and big block pontiac has pontiac block and olds has olds block

i think that the buick and olds are the same block but idk

YES chevy and pontiac are very different NOTHING interchanges

 

buick and olds are not the same, even though they have common displacements. both also have "small" and "big" blocks, with the primary difference being taller deck heights for the big blocks.

 

once again I was wrong

 

It can be done very easily. I put a 455 pontiac in my 85 chevy truck when the engine went. Just had to drill new motor mount holes, relocate battery to other side, install $60 trans adapter plate and install gen 2 firebird headers. There is nothing interchangeable with chevy engines. I did this because I had the engine and didn't want to put more money in the truck. Total cost was under $200 for swap. I ran this for about 10,000 miles before selling the engine. Gas mileage was about 8 mpg. Lots of torque though! The 350 400 455 pontiac engines are all the same size externally. They are wider than chevys and easier to change plugs because they are above the exhaust.