My modified Ryobi turns an 18 x 6 prop at 8500 rpms, and it has the stock reed valve so I don't think that is a limiting factor. I am going to put a larger prop on it, because I have heard of Ryobis blowing up when run this fast. When looking at that stamped steel rod, I am rather amazed that they hold up at the recommended 7500 static rpms. 7500 static will unload to 8000 plus in flight anyway.

AV8TOR