Depending on what boat it's on, you might look into the old 2 stroke factory prop. Same price as the current 4 stroke prop (which is a 9 7/8 x 10 1/2"). The 2 stroke prop has a little bit more pitch with basically the same overall design-worth a couple MPH on most tin boats with little to almost no loss in holeshot. The only time I saw any difference was if I was running real heavy. Extra passenger, more gear, extra cooler, running in a lot of current going up river. It needed all the help it could get to get on plane and the 10 1/2" did well. Only problem is the tach and RPM. It would run 6200+ (bouncing the 6250 limiter) if I didn't back off at full throttle.