Lead fuel additive was one of the greatest hoaxes ever pulled on the American public. Initially lead was added to gasoline to up the octane and was also touted as an upper engine lubricant. Hooey!!! What lead did was poison the environment(think about it) and cause the automobile engine to wear out sooner(neccessitating frequent replacement). The function of oil is to create a barrier between metal parts to reduce wear. Let's add metal to the fuel to lubricate the metal engine parts(yeah, right)! By example, modern vehicles do not use lead and can run easily to 200K miles without major repairs, the spark plugs last longer and the oil is changed less often(another ecological and economic benefit). Cars of yore ran 100K(maybe), they needed to be tuned every 6,000 miles or so and a 3,000 mile oil change was a ritual. So my advice is to keep lead additives out of your tank and run a high octane fuel if you need to. Ray