I would say that is the first thing you need to check. The head to piston clearence. I know a few guys have said to do it. You really need to see how far the piston is hanging out of the cylinder and than run a squish test.

Bring piston almost up to TDC and get a piece of solder an place it across the top of the piston. From transfer port to the opposite transfer port. Install head with gasket or no gasket if you are running an o ringed head. Tighten head down and rotate the piston up and past TDC. Remove head and post picture of solder and measurements of solder closest to the bores edge and where its no longer smashed which would be toward the dome of the piston.

Also post a picture of the piston at top dead center.

What base gasket thickness are you running?

I am wondering if it was a trinity cool head. They were known for there turbo cut domes but also known for cutting the dome not with any divergence in the dome but with a convergence into the squish band.