That's the problem with trying to make products for older, non-CNC manufactured engines. They are made with such sloppy tolerances, that you end up with parts that don't fit a lot of blocks or heads because your parts are made with more precision. I've been down that road for over 20 with Chevy, Ford and Dodge. The newer engines like the LS, Hemi's and Coyotes are much closer tolerances and easier to make parts for.
