With Powerflow? I fly mine somewhere between 9,000 and 15,000 feet here in the rockies and with a headwind, when I want to go fast, I'm at 2450 RPM (supposedly the RPM that maximizes the Powerflow) and leaned to where I have two cylinders >1,400 and 2 < 1,400 and CHTs < 365. With a tailwind...