Rotella T 15W40 - 1210ppm Zinc and 1110ppm Phosphorus (this is in the New Rotella T Triple Protection (CJ-4 blend oil)
Valvoline VR1 20W50 - 1400ppm Zinc and 1300ppm Phosphorus
Valvoline VR1 Straight 30 - 1400ppm Zinc and 1300ppm Phosphorus (same as the multi-viscosity in this regard)
So, they're loaded up with almost twice as much as today's 'SM' rated oils (which are around 600-800ppm). Most of what I've read says flat tappet engines need 1200ppm of ZDDP, but there are a few writers who say we need as much as 2000 ppm (even higher during break-in of a new cam).
For reference, Rotella T in a 4 liter (approx. 4 quart) bottle is $19.99, as for VR1 20W50 I was able to pick up a case of 12 1L bottles at Napa for $5.79/L on Monday - after taxes and the environmental fee, it was $79.10 for the case (Canadian dollars).
NOTE: I had to negotiate that VR1 price, the first store I was in wanted $7.69/L - I walked out when they kept answering phone calls instead of taking my order - went to the next NAPA store two towns over, smiled and chatted with the clerk, asked for a good price and voila Customer Service!!!
