In years gone by, different octanes of AV gas was a different color. So according to the requirement of your engine, you checked to make sure you had the right gas. Now a days, all that is available is 100LL, and as far as top end lube goes, that LL means low lead. Us in the aviation world call it lots of lead. It already lubs the top end, so I don't see the need for any extra lube. But it also causes a lot of problems also, like stuck valves, and leaded up plugs. They are working on a unleaded AV gas so they can get rid of the lead.