My O-320 is low compression (7-1). Runs like a champ (LOL, it's in a '66 7GCAA built by Champion) and probably has the same HP as the 160 HP version that has to run 100LL. I know this cause it has the same prop as the new ones and I get 2500 RPM on TO and can redline it going flat out. Thanks Lycon for the nice valve job you put on the new cyls. The plane sits in my hangar that is not temperature controlled so it gets hot in the summer and cold in the winter, and flies maybe 1/2 hr each weekend. My plane is in my back yard (as is my grass airstrip) and runs on the same gas I use in the mower. It starts perfectly and all I have to do is pump the throttle once or twice before hitting the button. Not at all like the IO motors that you have to start with the lean lever. But I ONLY use non-jokenol fuel from a station that has clean fuel with no water (I filter through a Mr. Funnel with the green screen).

That lead in an A/C motor gets into the oil. When I bot the plane the first thing I did was remove the freeze plug at the end of the crank to check for corrosion. The whole front of the crank (they are hollow on the snout for variable props) was filled with gray colored paste from the lead deposits. Now my oil stays very nice (Airwolf filter) and the plugs look great when I swap them up/down at 50 hr intervals.

As for running it in a car motor, the lead should help a little but may have the same effects I had on the plane motor with the plugs / oil. How much lead is in C-16? That stuff makes my plugs porcelain look yellow. Thumper, I sent you the wrong plugs, those ones were not from the motor that old Dom ran on.