Originally posted by tcodi
There is no way you could propose a good argument to put lead back in gasoline. It just cushons valve seats and takes a tiny bit of extra effort to build them tough enough to do without. That's it.
It doesn't just protect valve seats. It significantly raises octane, protecting cyclinders/pistons without need to retard timing and lose power.

Your alarmism re killing off all the birds and poisoning the planet is not worth addressing.