I am wondering what prop to use and what RPM I should expect with this engine. I saw a gentleman used one on the Skyshark P-40 and had a 20x10 on the engine. But he gave no RPM's. I have tried to e-mail him without sucess....
With an APC 18 x 6 or 18 x 8 propeller and the stock muffler, we usually see RPM levels in the 8,000's. With a different exhaust system, you can get more RPM, but the noise level will also be higher.