AvGas vs Auto Fuel:
http://en.wikipedia.org/wiki/Avgas#Grades
Octane rating:
http://en.wikipedia.org/wiki/Researc...rement_methods
AKI:
Anti-Knock Index (AKI)[edit source | edit]
In most countries, including Australia and all of those in Europe, the "headline" octane rating shown on the pump is the RON, but in Canada, the United States, Brazil, and some other countries, the headline number is the average of the RON and the MON, called the
Anti-Knock Index (
AKI, and often written on pumps as
(R+M)/2). It may also sometimes be called the
Pump Octane Number (
PON).
So, what's wrong with running auto gas in the lower compression O-320's if Auto fuel has the correct anti knock ratings?