Adam,
I've a 326 with 2GM20F and Campbell Sailer recommends 3RH 14"Dx8"Px1. I have to re-pitch it to 7"P to be able to reach max rpm 3400. I suppose your boat displacement is lower than the 326 so 14"Dx8"P may work for you. Then again it also depends on condition of your engine.
BTW, my stock prop was a 2RH 15"x10"P able to push at 3600rpm max.