Hi FFDQ, I am running a 18x6 wide APC prop on a G26 on a older hanger nine stick and I turn it a little over 8200 RPMs. I run a 17x6 standard APC on a G23 mounted on a Jerrys big boy and it turns about 8600RPMs. Have you peaked the G26 engine? I am running a B&B muffler on the 26 and the stock muffler on the 23.Hope this helps you know to expect from you engine. Wayne M.