I am real new at this whole prop thing. I have finally got my motor running strong and now need to address the problem that is my current prop. Its a little beat up but not horrible. I cannot find any markings anywhere on inside or out, so i dont know the pitch of it. is there any way to calculate the pitch by measurement? I have a 72 crestliner appollo 16 ft open bow real deep v boat. I would say the total weight motor and all is about 1500 lbs. The motor is a 1972 85 hp johnson w/ elelctric shift. Right now the boat can rev well over 6500 rpm and the motor calls for 5500 wot. I can do 28 mph at 5500 and can do 30-32 if i over rev it a little. I dont run it like that though, I just did it to see how much over the recomended wot it would go. The hole shot is good, but i would like to get the wot down to the 5500 and get as much top end speed in the process. I was thinking about maybe a 13" 19 pitch, but i really dont know. Any help or suggestions would be great.