I'll take the other approach and suggest that you will get more bang for the buck from a big block for the same money you would spend on a small block. The BB will make power from just over idle up to max revs if you build it properly. I don't think you could get that range of power from a SB without using a blower and blowers are pricey. Arrange your build around a 454 with 049 or 781 iron oval port heads. Pat McCarthy or Jerry Clayton can fill in the blanks.