Your old engine will run on unleaded fuel as is. With heavy use or continued use, you will see some valve recession (seat wears until valve sinks into head). When that happens, valve lift and performance will decrease.
Hardened seats are the normal solution. Valve guides are replaced due to normal wear. Stainless valves are an upgrade. My builder does all three, but he says that only the exhaust seats need to be replaced if the intake seats and valves have no damage.
Do you have a grade of fuel with sufficient octane for your engine? Is it a 326 HO, or a 326 2bbl?
Vikki 1969 Goldenrod Yellow / black 400 convertible numbers matching
