How do you word/edit a fuel placard if either 100LL or 91 autofuel can be used? As in, with ethanol?
100LL is preferred, and I intend to use that whenever available, but I'd like to be covered for those instances when caught in a pinch. It's for an AeroVee engine which I assembled myself to handle either fuel.
I'm looking for specific FAA legal words. Is it:
"100LL *OR* 91 octane auto gasoline",
"100LL/91 octane auto gasoline",
...or something different?