I agree that it's possible to ruin a valve, but unless someone is beating a 70 year old engine to death auto-crossing it or some other foolishness, you're never going to damage the exhaust valves. High rev racing engines or engines operating at the redline all the time are in danger of burning valves.
Driving antique vehicles under normal circumstances at normal speeds and normal loads won't hurt them.
I've put a couple hundred thousand miles on The Bismarck over the last 25 years. That included highway trips of over 500 miles at 75+ mph as well as local stop and go driving. It has only ever had unleaded fuel in that time and the heads are stock.
The same is true with the other vehicles. Drive like a normal human being and you'll be fine.
Also good to know. Thanks for your experience and input.
Although I don't completely flog the heck out of the Grumman, I also do just tend to drive all my vehicles, even my 1970's motorcycles I've rebuilt and ride regularly, like they were built in 2026 and just ride the heck out of them.
That being said, those engines were designed for unleaded fuel.
I guess it won't hurt anything to add some lead additive from time to time, but I also won't worry about having to do it every single time I fill up with fuel.
This begs the question, is there some way to find out if I have hardened valve seats without pulling the head?
I appreciate all of the input from everyone. Being new to working on these 4 wheeled vehicles, I'm learning a lot of important details the more we chat.
