[chap52]

Foil check the clearances.
With the head removed take small balls of aluminum foil (or modeling clay) and place them in several places on top of each cylinder. I dip the foil balls in wheel bearing grease to hold them in place. put head gasket on, put on head (no nuts) without tightening it down. Now slowly turn the hand crank through a complete revolution. Lift off the head and using a micrometer or calipers measure the thickness of any squished foil.
On the old V8 flatheads we have used a grinder to deepen head recesses and/or run double head gaskets as suggested. Never a problem. Chap