some stp has the added zddp additives
red or blue bottle,stp has some oil stabilizer with the zddp and is added by the quart bottle
if you can find it..think they stoped,I stocked up on it last yr,got 6 qrts left
I also have gone roller cam for this reason with the oil and have gone to the napa 10/30 with the stp oil stablizer
there is..
GM eso oil additve from the chevy stealer
use some 15/40 deisel oil like the napa fleet grade 15/40 this still has a higher level of the zddp in it also
theres more snake oil out there if ya check around