Quote:

A 400 Big Block with a .035 overbore and a 3.91 crank will make 470 CID.

A 383 Big Block with a .060 overbore and a 4.375 crank will make 511 CID.

Assume Stealth or Edelbrock Victor heads Forged crank, rods, and 7.5:1 Cr pistons and a 6 or 8-71 Supercharger.

Which one is the best?

Why?



I'd think you're going to have a hard time with that long of a stroke in a low deck to get pistons with enough dish for that compression, unless you're using super short rods, which would induce major side loading.

if you plan on actually running decent boost to not make the blower a poser piece, I'd probably stick with a 3.75 stroke (451 or 432 depending on block) max and run as long of a rod as possible to minimize side loading and to help the block live. a stock stroke 383 or 400 should be able to make 700+ HP on pump gas with a blower pushing 10-15PSI without turning the revs to the moon, which is pushing the limits of a stock block.

I'd also minimize overbore as much as possible to maximize cyl wall thickness.

assuming pistons at 0 deck....

for a 432 (.030 over 383, 3.75" stroke) with eddie or stealth heads (84cc) and a .040" head gasket, you need a 40cc dish to get 7.5:1. up the stroke to 4.375, you need
a 65cc dish to get 7.5:1...not gonna happen....

for a 451 (.035 over 400, 3.75" stroke) with eddie or stealth heads (84cc) and a .040" head gasket, you need a 48cc dish to get 7.5:1. up the stroke to 3.9, you need
a 53cc dish to get 7.5:1...not gonna happen very easily

stock stroke, you'd need a 28 and 33 cc dish, respectively...

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