Quote Originally Posted by 36 sedan View Post
JMHO, with a flat tappet, I wouldn't gamble on running without ZDDP for just a few extra bucks an oil change more.
I agree, but you need to measure carefully and follow the specific additive directions because too much ZDDP can result in the Zinc precipitating out and being deposited on surfaces of highest pressure, leading to premature failure. I believe you'd be safer using an oil that's formulated with more ZDDP than using additives.