So we have drilled holes in the deck, and drilled holes in the head gaskets, and when they keep leaking, we're looking to blame the guy that supplied the heads?.... Moparts at its finest. Maybe a legit modification (????), but you can't really be surprised that they're leaking.... Can you? How about trying a set of gaskets out of the package and onto the block without taking a drill to them, and see if that works?? If it does, then you know that the modification is to blame.