Tig,
You have a good set of heads there. Would the B1/MC's make more power? Yes, but I would build the 572 and if you move up to the B1/MC's later, they will work fine on the 572. If you think you would buy the PSO's or Predators later....and that's a 15-20k deal new, then build the 604. Believe me, I know, there are also 2 sweet deals for sale, Diablo's B1/TS and Pete's PSO motor. You would be money ahead even if you bought the $6000 Predators for sale. There's a lot more than the cost of some parts involved.