From
Bob is the Oil Guy "Motor
Oil University". This was written nearly 11 years ago, so things have no doubt changed. For example, SN grade
oil is now widely available, while the article indicates the author was looking forward to SM.
The following is from Part 7 - the link at the bottom is to Part 1. Read through all 7 sections for the full picture.
Concern: People are worried about the SM oils not having as much ZDDP as the SL and older oils. The reason ZDDP has been used for years is not because of its superior performance but rather its low cost and dual function as an antioxidant. It also has anticorrosive properties.
There are other additives. Some newer oils do not have any ZDDP, and they are excellent products. Just the same, I prefer oils with ZDP for now. The research shows that 0.03 is all that is needed and has the same function as higher levels. The only reason to have more is because your engine is consuming the ZDDP secondary to borderline lubrication from oil alone.
And lastly, too much can be corrosive itself and has shown in some tests to actually increase wear.
https://bobistheoilguy.com/motor-oil-101/
I don't know what oil was used for breaking in the cam and lifters as that happened long before I purchased it, but for the past 6+ years I've used SM or SN grade 5W30 full
synthetic oil in the engine without problems. A high lift solid flat lifter cam with stronger valve springs is likely more subject to wiping lobes than my lower lift, hydraulic flat tappet cam, albeit with double springs w/dampers (open and seat pressures unknown).