I am back to driving my TR3 after a few years of storage. I have some consern about using unleaded gas. The first engine lasted 100,000 and was rebuild in 1981. I have since put about 30,000 on this engine. I do not know if the harden valve seats where used or not. I need opinions on weather you would use an additive to replace the lead or just not worry about it. I know we have many experts on this board. Your opinions are appreciated.