well my rpm maxed out at 6500 i was running a 20X8 prop, i even had a 20x10. neither gave me the power, i couldnt go any leaner on the engine or it would die out. It was wierd I would pull up the nose and u could hear the engine bogging down, almost like it was leaning out, but I couldnt go any richer or the RPMs would fall off and couldnt get off the ground. I have a brand new kit in the box and I dont want to drill the holes for the fuji and ruin the mount. I guess i could send it in and have it checked by fuji or something.