What carb?

You don't mill the heads to zero deck. You mill the block. Was the block milled? Do you know your MEASURED static compression ratio? That cam is a serious hydraulic cam. It lowers cylinder pressure like no tomorrow, so it should have been advanced to down around 100 ICL. Do you know if it was? You may have a 450 HP long block, but IMO that intake will not flow it with what you have. An Air Gap or LD340 probably would.

So, your questions to answer:

Static compression ratio?

Was the BLOCK zero decked?

Where was the camshaft installed? Straight up? Retarded? Advanced?