I just got off the phone with Mobil (1-800-askmobil) and they tell me their 15W-50 Mobil1 has 1,200 PPM ZDDP. Their 5W-30 has 800 PPM. Their 5W-40 Turbo Diesel
oil has 1,100 to 1,200 PPM ZDDP. Keep in mind that
all Redline street oils have at least 1,200 PPM ZDDP right out of the bottle.
I'm using Redline 5W-30 (9 quarts) with 4 ounces of their ZDDP additive which gets me to almost 1,500 PPM ZDDP.