There are several additives available with ZDDP.
The one I use is STP in the blue bottle (1/2 bottle per change) with moble one synthetic.
That's in a Bent 8 though (it's my designated beater / plow truck).
So roughly 7 Quarts 10W30 Mobile 1, and 1/2 bottle STP.
Last I checked their website, STP still had the ZDDP, but I only use that vehicle to plow my own driveway and haul trash anymore so it doesn't get alot of miles.
I rebuilt the engine a few years ago due to the cam going flat and a certain brand of orange colored oil filter letting the metal from that score the mains and rods.
That was before I started adding the STP, or using syntheic in that engine.
