It depends on the size of the crankshaft pulley. Normally, the low mounted water pump engines have the big crank pulley and the 7" water pump pulley that bolts onto the pump. Early 235's ands 216's run the smaller crank pulley and the high mount water pump with the small diameter pulley pressed onto the pump shaft. High mount pumps can have either a 3/8" or 5/8" belt, depending on the year of manufacture.
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!