If you are looking for low to mid 900 HP, using a big bore block, and building with all new parts, then the 572-13 heads are probably a better starting point. Using the better head allows you to soften up the camshaft a little bit which allows the parts to all live longer. So you can make the same power but have a longer life.
I agree it would be easier, but already have 345 CNC-1s on my engine and I was trying to soften the blow to the wallet by reusing them. Going to 572-13s changes everything. I have been 5.47 with my setup at 502 cid with an iron block, and can only go 5.35 on a 8.50 cert so my thinking was 540/aluminum block should put me there pretty easy.
If I was going the 572-13 route I would build a 572 and not a 540.
I really don't want to go much faster in the old crate anyways....
