You won't see bearing shavings. You'll see metallics all over the cam galley, up high, if you pull an intake on a flat tappet engine, running conventional oils that have no phosphorus.
It has little or nothing to do with zinc. Flat tappet engines need phosphorus.
When buy a flat tappet cam, they parkerize them, just like a gun or knife. It's a heat activated coating of phosphorus and becomes embedded into the surface of the cam lobe and lifter, in a circular pattern, during break in.
Unless you put phosphorus back into your oil, as of 2011, there is no zinc and extremely low traces of phosphorus, if not zero, depending on which conventional oil you are running. Catalytic converters hate heavy metals, because it screws up the platinum, pulling hydrocarbons, so manufacturers took it out.
Zinc helps with longivity of oil life. Phosphorus helps with surface tension. The idea is that the high strength of the material from the parkerizing and in the oil equalize the strength between the two surfaces, so the two surfaces don't begin to sacrifice the weaker of the two components.
I have yet to look into Kendall, but I know that Brad Penn is running the original Kendall foundry, with the same people, even, and the same formula as the original GT-1. That is Brad Penn's Penn Grade 1 oil.
