Hello!
Anyone have any experiences with 100 octane low lead Aviation gas?
Thanks!
Godspeed,
thissideup

I'm using it ....in the Airplane.

More seriously, what are you hoping to use 100LL in?? Several of the guys I race with use 100LL in their stock '04-'06 Polaris 440's. That would be the HiComp head, not the trail head. I always used about 105 octane, a mixture of 110 and 90. I always felt I could lean on the motor a little more and get more HP out of 105 octane. Some of the guys I race with had good luck running 100LL but they had to jet at least one size fatter than I did. When we got our '07 440's they seemed to have a little more compression for some reason and noone tried 100LL, we all used a mixture with somewhere around 105 octane to be safe.

Compression is not the only thing that determines octane needs, Not even close. Ignition timing and Port timing also play a big part, as well as other things. But if you have 150psi or less cranking compression and relatively stock port timing you should be fine with 100LL as long as you don't dial in a lot of ignition timing or lean it down too far.