Fuel Fill Markings

[rodsmith]

With a renewed urgency to remove lead from avgas, I am wondering how to mark my fuel tanks. I will currently be using 100LL and at this point don't plan on using auto fuel, although I might change my mind in the future. My engine compression ratio is 8.5:1. I'm not sure what the minimum octane I need is. For instance could I use the swift 94UL. Right now I am thinking of placarding the tanks for 100 Avgas.

[marcusofcotton]

I would placard it "minimum octane 91 gasoline". And I would always plan to fill it myself with what I choose given current conditions. That way if there ever is a mishap and the lawyers get involved, at least you haven't violated the placard if you had put something lesser in it.