"add this to any 5 qts of oil you are good to go....."
An engine really will last longest with the right mix of additives for the oil, engine and use. Adding excess ZDDP is not a good idea, and adding to an oil that doesn't use it at all is probably a bad idea. If your going to add ZDDP, add it to an oil that's already has decent amount. At least that way you know its part of the formulation. Try not to exceed 1400 ppm Zn or Phos.
