Yeagerb came over last night and needed .020 taken off a Tri-z head. This is the first head shaving I've done. The plug hole is 90 degrees to the deck surface so it can be easily chucked up in the lathe and checked with the indicator. We had .001 runout prior to turning. I think it turned out pretty good.
Next experiment will be with squish bands and piston dome profiles. I'm not re-inventing the wheel here, but it just goes to show what can be accomplished in a home garage.