Ollie..Gentlemen......I remember several yrs back someone did some testing of a number of different prop manufacturers (can't remember what magazine it was in) and their props and found that there were a number of props that weren't made as "Advertised".....I.E a 22x10 prop that was actually closer to 22x9, etc....These abnormalities could explain why some props "appear" to work better than some others....I've found for example a 22x10 Menz prop works better than a 22x10 Zinger......The Menz props hub is much thicker than the Zingers hub and I've found that the Menz prop doesn't flex like the Zinger prop..so performance is better..also maybe the "advertised" pitch is more accurate on the Menz......These abnormalities might also just be one more reason to "test" different props to get the best results......of course keeping in mind what it is I'm trying to achieve........Bill....