3w 42i
TD1,you have a exellence engine,the prop that you have to use is 20x10
I use this engine with MenzS 6,950 rpm,
MenzUltra 7,420 rpm,
Zinger pro don't remember
3W 6,710 rpm
I have a Mejzlik 22X8 that i'm waiting for a few gallons to use it.

I suggest the 3W prop.The feel the engine and the plane with these prop much thusp and all around better power.

-is very important that you make a good breaking procedure.

Oscar Silfa