what additive to use for a 1962 car with only Unleaded gas available ?
Unleaded gas works fine as long you dont run it on long trips at high RPM.
for what octain? for a cleaner? for lead?? what car? what engine? what compression? checker/or autone/or pep boys sells stuff like 104 plus...but have no idea what your trying to do !
There is a lead substitute made for those vehicles, CarQuest has it in my area.