From the famous Gene Berg Quote:
ALL" factory VW air cooled heads from 1967 and later with the hard chromed stem valves can run unleaded fuels just the way they come from the factory. "ALL" VW heads have steel intake seats, hardened steel alloy exhaust seats, brass guides and tri-metal exhaust valves which have hard chromed stems.
Proost! Peter.
1954 Oval L275 (in progressive refinement)