Av gas is for airpalnes.... ;DDDAnd that is wher it should stay...The octane rating is measured different than automotive an racing fuel, such as VP c-12. the Octane rating is for fairly low RPM engines , (most prop planes redline at 2200 rpm) and there ratings are based on this RPM, and pumping efficencies at altitude, which is not accounted for in land based octane ratings.....Just as a side note , I have a pilot and Aviation mechanic that I work with, he uses 94 premium from the gas station because his planes run better , and it's cheaper...also Av gas has an oil dispersant to keep from fouling plugs...it tends to wash oil off cylider walls causing damage...But it is your wallet, I would rather run the E-85..it's more available and it is good for about 10% HP right off the bat...