I have a 1977 440 with flat tappet hydraulic cam is there any oil out there off the shelve with the required ZDDP to run in this engine? If not what would be a safe conventional oil and what is a good additive that I could use that is readily available again off the shelve?
I called shell oil technical support and one of the engineers ahs confirmed that Rotella T4 has is also for older flat tappet engines with 1200 ppm ZDDP.
