Over the Counter Zinc Additive

When you are breaking in a flat tappet cam,.......I don't think that too much ZDDP can be a bad thing, period.
If you choose to use the modern oil of today, afterward. Your cam will have a shorter life then you're eng.
In other words, you will go through a few camshaft in the eng life. If anything in the valve train is not quite right. The cam life will be shortened even more. That could translate from days to years.

ALL the manufacturers had to either stop production of a motor or convert it over to roller lifter before the oil change could happen.
I truly believe that was why the jeep 4.0L(inline 6) when to the waste land. Chry should have made a double overhead cam with V.V.T. and that 4.0L would have RULED!........Ok that's a hole nother subject.:mob:

Bottom line ALL engs need a little ZDDP , we still have sliding part on are engs (piston rings sliding on bores for one)
Sliding, while spinning, flat tappet lifter require the most ZDDP.

And some will say, Ahh it a stock lift 318 with stock spring........It will be allright..........
just like tossing them loaded dice that come up roses every time,...........You will win every time until the casino escort You Out. aka, it a much higher percentage of success.....but it's going to bite you in the end. :wtf::D
just my opinions :poke: and some of it is from experience as well.