There isn't huge differences.

Ralph allows more deviations from factory casting number parts, more aftermarket blocks,siamese bores, etc.in Supercars.

Come on out to a FAST race to see what it's all about. I am 50-60% sure I am going to the Mopar Nats, Not sure if Jeff P is coming, Don't know which car Tom C is bringing, but there should be a few smallblock mopars out there.