Early 216's with a specific cylinder head used domed pistons, and only on pre-1940 engines. 216's that came out originally with flat top pistons cannot use the earlier domed ones without getting piston/head interference.
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!