Been driving my 235 on unleaded gas for 15 years. If I ever rebuild the head I might go to hardened seats but maybe not. An old timer was told me to add one cup of Auto Trans Fluid (ATF) to every tank of gas. Being naive I thought if one cup would work, a whole quart would work better! Not true! It hissed and popped and smoked until the gas tank was empty! Never tried it since.
