I finally found some different props to try. I am going from 6" hub 4 blade 15 3/8 X 26 to a 4" hub 16 X 25 3 blade. My old props I could only turn to 4200-4300. How many rpms do you think I will gain if any from these new props. I also changed my drives from turning out to turning in now. I also had a porpois problem in smoother water. My drives are number III speedmasters.

What do you have for power? What size boat? Just curious as I am putting 3's on my boat

It is a 28 Pantera with twin 425hp 454's and number III speedmasters with the 1:33 ratio.

Ok about as far from my 40' with 650-700 and 1.5s as you can get lol. Sorry I'm no help on the rpm but depending how my prop testing goes I may be interested in yours

I think your still going to be too big.. You need to spin those motors about 51/5200 and with the increase in diameter I don't think your going to pick up that much maybe 500..

Yea I am worried to but I hope you are right with your 500 guess. I would be happy with 500rpms, atleast I am getting closer, LOL. He also has a set of 14 1/2 X 24 4 blades. I told him not to bring them though. I was told I need atleast 16" diameter for transom lift to try to stop some of the porposing. What do you think Excal?

Sorry miss print those 14 1/2 X 24 props are 3 blade too.

I was able to spin the 16 X 25 3 blade to 4800 maybe 4900 rpm Sunday morning. My eyes were watering to bad to see for sure lol. The boat seemed to be riding very good and stable in the flat water.