After break in I tested my new ASP.12 with 7" Master Airscrew props Fuel was Sig 15% nitro 20% Castor. OS #A3 plug. 7X4 2 blade gave 16,500. But the 7X3 gave a nice 18,300!! Seems this engine wants to rev. Tried a 7X4 3blade MA just for kicks and got 13,700.