I don't want to mention a brand 'cause I don't want to have people think I am suggesting anyone use anything other than straight motor oil. If you want to increase the content of ZDDP in motor oil, the easiest way is to buy a flat tappet cam break in oil additive. Companies such as Summit Racing sell them and the shipping is very reasonable. I typically use break- in lube itself, not an actual oil, but I am careful to avoid any of the break- in pastes as they are mostly moly lube which <may> be hard on wet clutches.
ZDDP is not illegal in any quantity in motor oil, anywhere that I know of but motor oil suppliers have reduced the content of zinc in motor oil because it is thought that zinc may coat catalytic converters used behind badly worn engines (with excessive oil consumption). The zinc content used to be between 1,200 PPM and 1,800 PPM but the new target seems to be 800 PPM. It is difficult to find out how much of the various additives are in each motor oil as the mfg. does not normally let that information out. I was told the other day that of the fleet diesel oils (Rotella, Delvac and Delo), Delo still has more than 1,200 PPM zinc content but I do not know if that is correct or not. Of course anyone could have an oil analyzed but I find it easier and cheaper to increase the zinc content than it is to actually find out what the base oil starts out containing.
In the end I believe that the currently available motor oils are perfectly fine for any conventional engine use simply because we are not seeing a rash of seized engines or galled camshafts; if the oil really were not up to the task we should be hearing of more engine failures, a number that would seem to be seriously close to zero in reality.
Brian
Hey Brain, what brand of cam break-in do you use and where do you find it? Beginning to think it might not be legal in PA since I haven't been able to find any....