A trick we used on race engines with radical camshafts was to install a head onto the block without a head gasket, adjust the valves on one cylinder to zero clearance, and turn the crankshaft. If we got no valve/piston contact, the thickness of the head gasket was the safety factor. The same test would apply to a stovebolt engine, and it would be simpler, even. The only valve you need to be concerned with is the intake- - - -there's no way an exhaust valve can get into trouble due to its angle and position in the head.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!