The more cu. in., the better. Why? You can put a bigger cam in while retaining a stock like idle. Unless you are under budget constraints, it would be silly to use a stock stroke 383 if you are looking to maximize power. Here is an option:

451 cu.in
Ported Stealth's
10.5:1 CR
Custom ground cam
Divider removed from DP4B
2 1/2" TTI and Ultra Flows

Easy 450 hp with a hydraulic cam, and never open the hood again. Or 500 hp with an agressive cam. All on pump gas.