**BEATS ME (at least at this writing - gotta spend some time w/my old books and, of all things, Google)And I still don't think we'll know for sure - Ford made process and manufacturing changes back then that probably are not documented so the average researcher could find valid paperworkpowerrodsmike said:Kewl, Dave, Good link.
So were Cleveland valves being made using spin welding? :thumbup: **
I notice that company started in business in 75, and is a supplier to GM. ***
***All you Chebbie engine owners take heed - us Fordnatics are still somewhat in the wilderness :sweat: :sweat: