Will a 454 drop in where a 455 came out of? Whats the difference of these engines and Is the pontiac 400 a big block?

Digger

 

No, the Pontiac 326,350,400 and 455 are all the same external dimensions, so there is no "Big Block" Poncho per se.

 

why would you put a POS 454 where a 455 was? the 455 would spank the living sh*t out of a 454, the 326-455 pontiacs were all big blocks, the only small block pontiacs were the 265 and 301

 

In addition to what TempesT68 said, Ive seen a 454 chvy & a 455 poncho on engine stands beside each other. THe 454 is physiclly a whole sheesh load bigger, and probably weighs more too.

You caint go wrong w/ a 400. I belive the 400& 455 have the same deck hieght, I could be mistaken, but use same rods. Pistons are different, where the wrist pins are located.

Try this: Either get 455 crank ground to 3" mains, or get new 4.25 crank w/3" mains to fit 400 block. reuse preped rods. Bore 400 .030", this gives you the standard bore of 455. Get new Standard size 455 pistons.

455 crank has 4.21" stroke, new cranks for 400 have 4.25" stroke.
think about it.

 

the blocks and decks are all the same size, the rods are also the same as mentioned, the only parts that are 455 only are the crank and pistons, a .030 428 will let you use standard bore 455 not on the 400's a popular swap is to grind the mains down on the 455 crank and put it into the 400 block to get a 440 storker, these are a mean engine! if not a standard 400 will make PLENTY of power not to mention fit in directly and cost alot less to build

 

The reson I ask this is because I want to buy a 2nd gen pontiac and put a 455 in it. I am starting to think that these cars are beter platforms for performance compared to the 3rd gen camaros. I say this because they came with big cubes and dual exaust. They are not as nice but more potential IMO. What are the prices of 455 performance parts compared to 454 parts?

 

Im still curious about this 455 option. I just got a 78 400 for $100 and I would love to make it a 455. so far I havent found anyone that sells new cranks though, atleast in the catalogs Ive got. what are the chances of finding a 455 crank used? also, if I got this crank, all I would have to do is regrind the mains to 3"? everything else is the same?