I was browsing through my local O-Reilly's lately to pick up some Sta-bil, and I found this:
It SAYS it contains ZDDP and that it's designed to prevent camshaft wear. It also has instructions on how much to add depending on the application and year of manufacture for your machine. For motorcycles, racing, and a few others it specifies 2 oz for every quart of oil. If I remember correctly, that 11 oz. bottle was priced around $6.
I haven't looked for an MSDS or a contents sheet, and I haven't contacted the manufacturer to get actual figures. I'm posting this here in hopes that someone else might do that. It sounded good to me, but looks can always be deceiving. Up until now I was just supplementing with about 5 oz of STP oil treatment that says it has "high ZDDP levels." It was cheap, and I figured throwing it on top of my Rotella wouldn't hurt anything.
**NOTE** I didn't want to post this over in the recommended boosters blah blah blah thread until one of the
oldfellers old timers decided if it was actually sufficient.