Funny thing is...I spent weeks and weeks reading everything I good about building engines and the "marriage of parts" and I think that I have thrown it all out the window.
I don't think you've tossed it all out. For example, those heads were used on 425 HP 454 CID big blocks in '71, and those cars certainly didn't have 3" exhausts or 3000 stall converters. And, the current 425HP 454 uses a little shorer cam (211/230 - 510/540). So what if it ain't perfect. It isn't a mile off, in my opinion - but I'll defer on the finer details to Pat or Johnny 0.