On 5/14/12 7:11 AM, Dave wrote: > last time I was in a flaps, the valvoline synthetic 20w-50 racing oil > had zddp > And that is what is in my engines. Even if the label states "not for street use". It does state that it is blended for flat tappet engines. Always look for that statement on any bottle of oil you buy. I get mine from NAPA. Teriann