Reeds vapor pressure is the first thing that comes to my mind with AV gas. Discluding octane and lead issues, the stuff is ment to be run at altitude, not sea level. Airplane engines and what we race are very different in design. They run valve seats 2-3 times as wide as we do with spring pressures well under what we run.
I guess airplanes dont take off at sea level. This is where they need the power.
Take off at sea level is no big deal in many piston powered airplanes, taking off at Denver in the summer in the middle of the day is a little more challenging
You have to lean the motor out for best power on the run up and know that the airplane will take around another 1500 to 3000 ft more on the take off roll to get airborne and then fly like a lame slug in that air density, keep the nose down and get some speed up before manuevering
I flew into and out of Denver once, I told the passengers to be ready for takeoff before 9:00 AM, which they where
The air density was still way above 10,000 at that time
That engine was a 540 C.I. Lycoming opposed six cyliner rated at 260HP at sea level., it had around 170 HP max at that airport that day in that weather leaned out
