I have read that SF rated oil is fine for flat tappet cam engines. However, SF rated oil is now obsolete. I have searched the net to try and determine what the SF rated oils had in the way of ZDDP (Zinc/Phosphorus) and found nothing.
Does anyone have info on what the actual SF specs were, for Z...
I went to the ZDDP forum on 8-6-09 amd asked this, what I think is a simple question, "What, exactly, is an acceptable level of ZDDP for a SBC with a flat tappet cam?"
No reply as of yet. Makes me wonder!
1976 Corvette. Rebuilt 383 engine with a CC 274H flat tappet hydraulic cam. Standard clearances on rods and mains. OCI no more than 3000 miles or minimum of twice a year.
Now using Valvoline VR-1 10W-30 because of their ZDDP numbers and it is no where near as expensive as the speciality oils...