No need to, Oz...exhaust valve wear is so minimal without lead it would take over 200,000 miles of unleaded gas to BEGIN any noticable problems. Hardening the valves is not necessary nor is adding lead
I was only because I could not get rid of a minor knock even after using high octane gas. The engine was in need of a rebuild at the time and both the high octane gas and lead solved/hid the problem.
I am not using lead additive ,( I was using on my 57 Studebaker) , but in the Bird is a 72 400 model engine. No knocking either , even on 'regular' , but since gas has gone down I am using premium for a little better performance!
