I've seen the valves float on a stovebolt engine occasionally- - - - -but only if it was installed in a boat. Getting a street engine up to valve-floating RPM might be possible, wide open in granny gear on a SM-420. Otherwise it's pretty unlikely. Stretching or breaking one of those limp spaghetti connecting rods would probably happen first.
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!