A 22x8 is too much prop for that engine. I fly with a 20x8 and get 6800 or so rpm. Never, NEVER, believe rpm numbers you see on the forum! I am convinced that half of them are questimation and the other half have very generous tachs. For instance, g-62's at our field running 22x8 menz props might get to 7100 to 7200 max. Now I know they will be down a few hundred rpms at our altitude, 5,000 feet, but I see posts all the time where guys are getting that kind of rpm with a 24x8. The other thing that makes me laugh are rpm numbers where changing a prop gives 20 or 30 more rpm. I don't know what kind of tachs are being used but they aren't that accurate. By the way I use an old Royal pro tach that is considered one of the best ever made and rpm readings aren't that consistant.

Larry