So you are sayin these heads aren't any good. I tried to post a link to them but it wouldn't work. Just do a search for them on summitracing.com
Chevrolet Performance Fast Burn Cylinder Heads 19300955
Those are the heads that's on the Gm 604 crate racing engine. We had that engine in a few of our cars and that is a good head. You should easily have over 400 hp as long as you have a decent cam but if you want to switch those heads out for something else I will gladly take them off your hands...I can't help you out with a header choice though case we used schoenfeld headers