Well anything that is mass produced is going to have what I call Go-No Go set of tolerances..
If you want it exact as possible that means CC each chamber, muli cut valve job and milling along with port matching...On our motors I usally get un-cut domes so I can fit domes to heads and flycut my own valve reliefs..Indy stuff has made it possible for Mopar racers to have some good componets to build with, instead of having to find 40 year old stuff to build motors with.