Classic/Antique Car Repair: leaded gas, valve seat recession, leaded gas

Question
I have a 1972 mgb with 72,000. It runs well, but I'm curious about gas. The previous owner used a lead substitute to compensate (he said) for the absence of lead in fuel available today. But I've talked to several folks since who use unleaded in cars and bikes from the same year.  What's up?  Do I have to use a lead substitute or can I run it on unleaded?

Answer
The lead substitute is a waste of money.  Your car definitely doesn't need it. If you were in the habit of driving across the desert for hours without stopping, in 110 degree heat with the AC going full blast, and pulling a heavy trailer at 80 MPH, you might see some evidence of valve seat recession after a few years, but I don't think that is a likely use of an MGB!

Relax- and enjoy your car.

Dick