i was considering getting a firebird. i was thinking 68 with a 400 ive heard that year was the fastest with that body style. is the 400 a small block and do parts such as pistons from the chevy 400 work on that engine. i was also thinking about getting an automatic. ive currently got a 66 mustang that ive rebuilt including a whole engine job frame rail replacement drum to disc brake swap and some body work so i am decently knowlagable on the basics of automitive work. what would you guys suggest. does a 68 with a 400 and an automatic seem like to a decently fast car or is there another classic firebird with a 400 that would be faster thanks in advance , J

 

The 400 is an awsome motor and is often overlooked. The Chev and pontiac motors are totaly different design's and nothing will interchange. As for auto-trans equiped car's, I would much rather have an auto(I've had both)...you will not miss a gear with an auto...just my 2 cents

 

Having ran a 9.31 e.t. at over 144 mph with a Pontiac 400 in my vega drag car (the chevy guys just don't know how to handle it when the hood is off!), I say the Pontiac is a great engine on it's own. The Pontiac V8 isn't a small or big block. It would be best described as a "medium" block, regardless of the cubic inches. Small vs. big block sizing is based on cylinder bore centerline spacing. It's not impossible to use a chevy 400 piston, but you will have to go to I believe it would a 7" long custom connecting rod.