I just switched to Brad Penn #1 . it says it has enough zinc and phosphate for flat tappets but I wonder if a half bottle of ZZDP on top of it would do more good than harm? I've heard too much is as bad as not enough.
I'm not sure.
after breaking a pushrod cup due to excessive heat from not enough lubricating value due to the oil and costing 5000.00+ to fix the mess(not enough zinc in oil due to longer catalyic converter life)i like to add my own to be sure..dont trust any politiacian's,lawyers,or corporations that say they have your back.u better cover your own a$$..i would do a search on the quatity of zinc in that oil and my flat tappet requirements..i run valveoline vr-1 with an additive,,the last time i checked,been awhile that had the most zinc in it off the shelve...it could have changed by now but my additive does the rest... to be sure..