with a 11:1 and alum. heads i find pump gas works with no ping (maybe)
however i do notice a 10-15 deg hotter temp with pump gas alone.
the "real lead" that was mentioned does exist and works well. i use 1\2 quart
of the stuff linked at bottom in a full tank and i can idle at traffic lights all i want
even the sound of the motor is better, it really likes it. this product is
tetraethyl lead. i cannot tell the difference in driving or plugs comparing racing
fuel(leaded 110) or 93 octane exxon\mobile with kemco's lead added
www.kemcooil.com/products.php?cId=4