The avgas is leaded and marketing materials “encourage” using it, FWIW. But yes the efficiency and heat output definitely differ based on the fuel used, some w

The avgas is leaded and marketing materials “encourage” using it, FWIW. But yes the efficiency and heat output definitely differ based on the fuel used, some will work better than others for a given stove design. You should be able to combust most of the hydrocarbons regardless of fuel source by adjusting the air intake but any non-hydrocarbon additives will produce strange byproducts which will seem like it’s not burning “cleanly”. e.g. SOx, NOx.