My shop is at the airport in my hanger and I pretty much use avegas in my cars (100 octain low led). Even use it in my model A. The cars have seemed to really like it , and the real reason I use it is because it does not break down or does not gum up the carbs or fuel lines even if it sits for 2 or 3 years. It is 100 octain and I was wondering about the engine set up, as in timeing. Also was questioning the led as there is a little lead still in avegas. Maby like foueling plugs, or a littli more carbon build up in the combustion chamber. In the aiplane I have to lean aggressively during taxie and then in cruse we run very lean, in fact quite a bit lean of peak EGT. I was thinking it would tend to foul plugs a little more since there os no way to lean auto engines without changeing jets. Any thoughts out there. Sharkey 5557.