Most Carter YFs have a slotted throttle base that fits both stud spacings. You still need a carb that's jetted and calibrated for approximately the right size engine. The correct venturi size is very important.
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!