Realistic valvetrain expectations.

No offense but if you're expecting 1.5hp/in from these dinosaurs comparing to the LS platform - it's considered to be a very strong build and it's not something anybody can do. It can be reached, but a lot of the reason the LS are so good, is they share next to nothing with the comparable 454's of the same era. Basically apples to pears comparison. You should probably decide whether you want 600hp, or 600tq, and build for that in whatever means possible. I.e stroke it. Otherwise you will be really spending on block prep, camshaft, and valvetrain to keep it alive at very high rpms to get those hp figures. Like 7K plus.