Hi James, the stock prop on our 331 is michigan wheel RH 15x11, with a metric taper. I just finished sorting out my new Campbell Sailor RH 15x9. It was not set up for 9 inches of pitch, so after having a diver re/re the prop, the prop shop showed me how over pitched I was, now I have 3600 at wide open.
These are excellent propelllors for the non racing crowd, I have picked up at leat half a know under sail, and 90% reduction of stress on the tranny.
I only suggest you have the pitch verified before you install it.
gord.