If the carb is on one side of the engine and the exhaust on the other, it is probably a homie. If the carb is o the back of the CARANKCASE, and the exhaust is on the back of the cylindar it is probably a RYOBI. However, RYOBI has built engines for other companies, I have a "STIHL" that is built by RYOBI, and I believe that HOMELITE now ownes RYOBI. To answer your question, I have a Ryobi modified with a bigger carb and C & H ignition that turns a 18 X 8 wood prop close to 7800 to 8000. It also sports a "FRANK BOWMAN" ring. We are at 3700 feet altitude, so I think that is good. FLATHEAD 4