Leaned out the high speed 1/8 turn. RPM with 18x6 Master Airscrew Prop 6,600. With JZ 17x6 7,700rpm. Flew with the 18x6. Good power no poping sound at high speed or 1/2 throttle. Some lower. More than enough power for the Stearman, good verticle but not unlimited. Cermark stood behind the product. I think this is going to work. We will see if the ignition last. Check voltage and didn't seem to be too much drain.