I'm looking at a used set of 452 heads, lightly ported (gasket matched) nice valve springs retainers & all that stuff. my question is they have been surfaced, quite a bit it appears. 1 needs to be surfaced again. my concern is, is there a way to tell how much has been milled off them? I know small block Chevy heads have a target spot to measure off. do the Mopars have a spot like that?