Boat is a 22 ft scarab advantage. Motor is a 383 stroker making around 350hp n/a. I am adding a blower to it this week and it should be making close to 500hp at 7 psi. When the boat was n/a I ran a 15.25 x 22 hydromotive 4 blade. It did good but now I am making another 150hp I am thinking I need to jump up to a 25-27 range. Not sure though. Outdrive is a alpha 1..... Shooting for 75 mph.

Thoughts?

You can use whatever prop you want cuz the Alpha drive is going grenade every time you push the throttle hard.

that is a lot of power for an alpha. i would go back to a 3 blade. less load on drive. better top speed. you don't need 4 plades to push a boat that size. need more perf info than it did good in order to make any guesstimates. alphas don't like to go over 5500 or so. fortunately they are inexpensive...

Go ahead and put a 5-blade on her, ram the throttles forward, and get it over with.

and usually people jump on me for breaking people's stones...

I had a 21 ft baja with a 350 sb blowen pushing 500 hp and ran it for years and never blew the alpha. I always took it real easy coming out of the hole. And actually I know the guy I sold it to and he is still running the same drive just a little less power behind it and that was 6 years or more ago. I would recommend changing drive oil often and run a drive shower. Sorry I don't have an answer for your prop question but I felt I needed to stick up for you and your choice to stay with an alpha, because it can be done.

Thanks, the only reason I am running it now is because its what is on the boat. I dont plan on trying to blow it up but if it does I will be upgrading to a bravo. I know it can live if I am careful which I plan on doing. Also I am installing a drive shower as well to help.

You're probably only looking at a addition 2-3 inches of pitch.
Call us and we can set you up with a test propeller.

Brett