Hmmmm, it's been a good number of years since I had researched that info... Now that I have RE-looked up the data again... You seem to be quite correct crackedback... I guess there aren't enough Old DIESELS on the road and (as you said) they have reduced "zinc" a bunch... I may have to switch to the OFF ROAD racing oil after all... I'm still against "additives"... but that line of thinking may also change for me. Though, I still do have a few "old" gallon jugs of the Valvoline Premium Blue left and LOTS of Mobil 1 15W-50 w/zinc.
So this thread has been enlightening and informative for sure... else I would have gone on thinking nothing had changed... I miss the old days when we had "LEADED" Fuel, lots of "ZINC" in ALL Motor oils... And more and more, the "STEEL" in cars is being replaced with plastics and now my Doc is telling me I have an "IRON" deficiency... What is with this "Metals" thing???
Guess I'll quit giving my Two Cents anymore (there goes the "COPPER" as if that is real anymore) Sigh~