I just got my hands on a 72 400. I'm new to Mopar so I'm not an expert. I want to know; If the block checks out good with magnaflux and a sonic check, and I spend the money on doing the aftermarket cross bolted mains and good high quality reciprocating assembly, say a four inch stroke for a 480 cube motor, what are the limits of this block? How much power and RPM can these motors handle? Where/what are the weak links? Can they take say 1000 HP 8000 RPM? How strong are these blocks?