I didn't think you could punch out a 396 that much. You would have to bore it out .156, I didn't think that gm designed the cylinder walls to be taken out that far.five7kid said:Hmm, it seemed to me that 454 parts were always less than those for 396/427, etc. But, I haven't been looking lately.
My block was used for both 396's and 427's, so I'm considering having it punched out to 4.250" next time it's apart. Certainly the bigger bores breathe better, and if you don't have anything to work with, it makes the most sense to build the bigger engines. These days, a 454 is considered "small".
I'm certainly not running 9's, but it has been very consistent for me lately.
For a 427 I've always heard to get a 454 block with a 396 crank, since the 454 already has the 4.250 bore.
I've yet to build one, so I could be comletely wrong here. :dontknow: