I just used the oil that I was going to run all the time - the only additive i run in my vehicles is lucas - had good luck with it - 83 3/4 ton chevy 6.2 209000 miles - 98.5 dodge 2500 cummins 270500 miles - 84 s10 blazer 2.8 around 130000 miles - 86 4x4 rx7 GMC 4.3 unknown miles when i built it - 88 rx7 with 350 engine around 5000 miles on rebuild - all run Valvoline with a QT of lucas - diesels 15-40 valvoline 10-30 valvoline the rest