Don’t know. The Stihl already turns 7100 with a 22 X 10 prop. I am planning to increase the duration by 1mm on both intake (10 degrees) and exhaust (12 degrees).

The G-62 had an in cowl Pitt’s muffler and probably less than an hour run time. The port duration is likely to be too wild to be effective without an expansion chamber. It would not be surprising for the G-62 to produce less power than the Stihl. Port timing alone is not the route to HP. Hope you have the Jennings book dissected and understood.


Bill