ok i'm swapping a 1987 v6 firebird with an automatic tranny to a big block not for sure on the size yet either a 454 or 455 i'm guna have to do the following which is pretty much a givin, shave the wheel wells, transmission, radiator, larger fan, exhaust, but would i have to swap the driveshaft, and rearends?

 

There's no 455 big block. That's a Buick, Olds, or Pontiac size. Much more trouble than a big block.

Do a search on this forum for the phrase "big block". Ignore the ones where they call a BOP motor a big block. This is the single most popular "swap" (I don't consider 3305->350 to be a swap, and hardly even 6-cyl->V8) done to them. There's guys and maybe gals on here with pics, instructions, before-during-after pics, parts lists, tales of woe, and everything else you could want.

 

well i might just go with a 454 cause this motor i'm lookin at is bored over and its bout the same price, so i'm pry gunna have to swap out the rear ends right?

 

no you can use your rear end.You could also use some more reading

 

The links in the sticky don't seem to be working.

However, there's enough in regular threads that a search would provide a wealth of info.