All good advise so far.....
About 10 years ago when I was with some buddies on a dirt track car we had a local Shell station sponsor our fuel... He would give us 10 gallons of fuel per night of racing,any kind he had.... Well, he had AV gas and we used it for about half a season,car ran good,no real problems,halfway thru the season we switched engines (we had 2 identical engines) and "freshened" up the first one,when we tore it down there was a nice black carbon looking coating thru out the engine... BTW,we changed the
oil and filter after every other race....
Talked to a Shell enginner later and told him what we found,he said AV gas was probably the worst thing to put in an automotive engine for fuel.... He said the AV gas has a number of additives for high altitude-air cooled engines-to prevent condensation and a few other things I can not remember....We began running racing gas again bought at the track and after a half season when we tore down an engine it looked almost as clean inside as when we built it....
Racing gas may be more,but it is made for race engines at mean sea level....
David