muahaaahaaa. I`m in love! this morning I pulled the sleeve on my mvvs 49 and dremelled it. I had measured the top rpm on the 12.25 prop on faI fuel at 13000 last time I flew it.Today after my grindig I measured the rpm at 13500 It will still develop even more power as I go through a couple of gallons. It now has more power than my asp 52 and vertical pull was even better.It maintained rpm`s and just climbed and climbed. My asp looses rpm`s as it climbs straight up. You guys with all the formulas how many % increase in power is going from 13000 to 13500 on the 12.25-3.75?? It all took only 30 minutes