Magnum intake drilling plate project

Stephen Hotz said
He has the added problem of a broken bolt in the end of the head.
The iron or steel nipples work better as they wear slower than the brass.
The tap used for this build is a 1/8" npt thread.

The tap is a 1/8-27NPT
The pipe nippple is a 1/8 MIP X 3in cut in half.
1/8NPT next to a 5/16UNC

The angled hole that has the nipple on the end is what sets up the initial location for the jig. Milling the heads is not a problem. The end 2 original magnum manifold bolt holes are the reference points.

When you mill heads you may face the intake side of the head if you take a lot off the chamber side but you don't redrill the manifold bolt holes. I don't anyway. lol