Thank you Pat, R Pope & Bentwings. One of the reasons I was asking about mixing is because it will be impossible to not mix unless I always run the aviation fuel. And I don't want to do that cuz the airport is to far away from my house plus they won't pump it straight into my car so I'll have to use 5 gallon cans. I tried octane booster & it didn't make any difference. Don't know how true this is but the guy at the auto parts store told me that octane boost actually raised the octane level so little that it wouldn't make any difference.... Is this true? Thanks again to all!!! Bill