[bmalone]

Back in the old days, valve seats were not a hardened material because there was lead in gasoline, which acted as a lubricant. As leaded gas was phased out, high-performance motors had a dilema to deal with. The answer was replacing the valve seats with a harder material that could withstand the contact. Of course, all motors today are built with hardened seats so that unleaded gas can be used.

I don't see anything wrong with running leaded gasoline.