In general AVgas will result in a lean condition. Air planes are all able to adjust mixture on the fly. For take-off for instance they richen it all the way up and cruising at higher alts they can lean it down. AVGas also is high in lead and will kill a converter and some O2 sensors may not work with it. I believe its stoichmetric ratio is a bit different meaning that the carb might need to be tuned. It also has several other additives in general that a car doesn't need but I don't think they hurt anything. I would be wary of rubber hoses etc until you get used to it.

Like Robot says though, you could keep an eye on the plug readings and try it out.

Kitz