[john in illinois]

The machine shop that I use has a dedicated head mill. They thread the holes and attach it to a fixture that tilts to perfectly index the head. they told me that clamping the head down distorts the head and when removed it is not flat.

They do a lot of race engines so they are kind of out of my league and my home shop Bridgeport. I think Mart could do one and have acceptable accuracy.

John