There's a lot of opinions about EOS. The new EOS stuff doesn't have very much ZDDP as the older versions. Too much ZDDP will kill a catalytic converter as well (phosphorus), so if you run cats, just be careful and not put a lot of it in. If you don't run cats, it's more forgiving to add a bit more. I've used quality oil, and have run about 3 or 4 capfuls of the old-style EOS (GM p/n 1052367) at every oil change on the flat tappet cam cars I have. The roller cam cars don't get any. Because it doesn't really need that much in comparison. The newer quality oils have different ways of incorporating wear additives. So it's not quite as critical, IMO. Obviously the additives built-in are better, but I don't think adding a little older EOS is a bad thing.
Also, I think manufacturers who are on the hook for longer warranty replacement on cat converters lobbied for reducing ZDDP content in oils due to having to not replace them as often. Because excess ZDDP can hurt the converters, but they may be playing it safe with the levels they say are damaging. Being very conservative. That's just my suspicion, that's not necessarily a fact.
Does my method work? Maybe. Too diluted with just that small amount? Probably. Do I give a flying crap? No. It may not do much, but it's still slightly better than if it wasn't there. So if it saves the lobes and give me some peace of mind, I'm all for it. I don't want to put too much in and potentially ruin a cat converter I can't replace with the original type. My tangible results so far seem to be good. I haven't had any flat cam lobes doing it this way.
