i have a 64 aqua craft 18' vdrive with a 500 hp bbc and hall craft vdrive gear box 12% to 18% od. i have a 3 blade prop and want to go to a 2 blade for more top end, the 3 blade has good bottom to mid pull but really loads down the motor and it wont rev much past 5k-5500rpms,from the research ive done it seems like 11.5" 2blade 15 pitch would be a good prop. is that right? can anyone please help give some experience and advice? thanks. jim.