Just picked up my rebuilt 4.2 from the engine shop. Head rebuilt all new valves guides, cam bearings and 12 new valves. Block got the full meal deal also, hot tanked then re-bored, decked, new conrod and mains bearings, timing chain, oil pump, etc, etc. No expense spared… don’t tell the missus.
After loading the engine on my F-150, discussions with the shop tech revolved around break in and which oil to use for the first 500. Having been a 20-50 man since buying the car in 1985, I was surprised that he suggested an oil I have never heard of. Hot Rod 20 / 40, available from most quality parts stores.
He is a long time engine builder with a stellar reputation and has built everything from mega racing engines to screaming rice rockets but the reason for his recommendation is that it contains zinc which is beneficial for the cam lobes and buckets. I intend to follow his advice when I fire up the boiler in a week or two, but has anyone come across this? best regards Brian / Mytype