I don't think STP has the zinc any more. They've taken the warning about zinc off of the bottles. I don't know if it's enough zinc or not, but I've been stockpiling some bottles of the "house brands" of oil additives when I find them that still have the zinc warning. Last time I checked, the local ALCO still had it & so did the Dollar General where I live. I don't really like using this type of stuff, but if it can save a flat tappet cam, it would be cheap insurance. Plus, I have a really loose engine in my current daily driver & this stuff helps to keep it from sounding so much like a diesel. :D
My next Mopar build is going to have a roller cam. Hopefully, this will make the zinc a non-issue. [-o<
:burnout: