RE: Why not a Webra engines thread?
Cus, I run an APC 14x12 on my P-5 which it now turns about 8,400, the 14x12 is the smallest prop recommended by Webra. In the case of this engine the extra metal/weight is a good thing since this engine is designed to work hard at sub 9,000 rpm.
Case in point, I tried the 14x12 on my SuperTigre .91 and only managed 7,300 rpm and quickly got very hot but my MVVS .91 turned the 14x12 at 8,100 and seemed to handle it with no complaints. What did you get for a muffler?
PS, you'll love the sound if you have this same muffler.