Sorry Hot Rod, but I must disagree with you on this one. My experience comes from working with the TRW company on engine development programs. Valve recession with unleaded fuels is a very real problem, and gets worse with speed and load, but even continued highway driving could rapidly ruin a head. It may vary with different engines, but it is a real issue, not some mechanic's myth!
The intakes are cooled by the intake charge, and don't need inserts. The exhaust valves are not. Their temperature increases with load. It has nothing to do with seat pressure.
Last edited by Woodswarrior; 07/27/2014 10:51 PM.
