I am old school so for 20+ years I have been using STP oil treatment which contains zinc to every oil change and never have I had any issues in my current 340 and my previous 440 R/T
I agree, it does. HOWEVER, be very aware of the store brand STP oil treatment. READ the label and you will find out that most all store brands do not contain any ZDDP at all. I know for a fact the Oreilly brand does not. So use the real thing.
