Not necessarily- - - -I've seen oversize pistons without a size marking, but most of them do. A simple $20.00 dial caliper from Ebay or Harbor Freight will be accurate enough to get a ballpark guesstimate about bore size.

Standard 235 bore: 3.5625

.020 oversize: 5.5825

.030: 3.5925

.040: 3.6025

Etc.!

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!