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The cheapeast wallmart brand oil available today is lightyears ahead of the best oil in the 70s/80s/ most of the 90s. Imo, I wouldn't worry about adding zinc. Especially in a hydraulic cammed engine.



While the oil is better in MOST aspects, its NOT better at lubricating the extremely small contact patch between a cam lobe and its lifter face. Zinc/Phosphorus is/was added to aid in this task.
Problem---modern engines have Catalytic converters, Zinc/PH deposits attack and destroy the reactive metals in a cat that are required in order for it to function. BUT----modern engines are roller cammed and do not require the Zinc/PH, so the EPA drastically reduced the Zinc/PH in oils so that cats will live longer.

Hydraulic or solid has nothing to do with it. Spring rates and lift does.

True a smogger 360 needs little zinc to live, but its still a concern.



Zinc Tunnel Vision...

Both the above quotes have elements of truth to them. Yes, zinc content in motor oil is of high importance with respect to flat tappet camshafts. However, there are other important aspects to motor oil quality that is worth a look as well. Such aspects include: Foaming Tendency, Volatility, Depositing, Seal Compatibility, Shear Resistance, and Sludge Control to name a few factors that contribute to a comprehensive motor oil package.

Being focused on zinc content alone may limit us from having a true performer in our motor oil. While an API (SG) rated motor oil from 1993 has the higher level of zinc we’re after, it also lacks in all the other qualities mentioned above.

If we can combine modern motor oil base stocks and a modern additive package with pre-2004 zinc levels; now we have the best of both worlds.