A lot depends on the type of camshaft follower the engine was built with. The zinc has been removed from today’s engine oil due to emissions requirements. Roller lifters don’t need the metal to metal sliding protection that flat tappets need. If motor is equipped with roller lifters then use modern oil. If flat tappet equipped, I would suggest ZDDP enhanced “hot rod” or racing oil. I’ve had good luck with Valvoline VR1. The high zinc Dino oil, not the synthetic version.
