My car currently has a 400 in it and i've just recently found a 454 for a really good price instead of stroking my 400 to a 427 like i'd originally planned to do.
Is a BB gunna fit right into my tranny? Or will i need a new bellhousing? i'm not worried about getting it into the car at all, just matching it up with my 700r4.
Thanks

 

The tranny should bolt up but I think all the other stuff involved in a gen 3 BB swap will be more of a PITA than it's worth.
I think building the 400 you have will be a lot more cost effective and much less headache.