Originally Posted By: ARCOgraphite
Many Mild factory v8s wore out by 100K miles running high zddp oils in the 60's and 70's. Big cam engines aren't going to last past 500hours anyhow - You want a roller there.
I'm all for modern engineering like roller cams, overhead cams, Variable valve timing, etc. but its flat out not true that big cammed, flat tappet engines are are going to wear out in 500 hours.
Roller cams have issues too, there is no free ride. If you use a hydraulic roller, you are essentially limited to 6,500 rpm before the lifter pumps up, ie valve float. If you go with a solid roller cam, then the rollers get beat to death when you are dogging the car at idle or low crusiImg rpm. Even choice has limitations.
whether or not engines were worn out at 100,000 miles has more to do with, maintenance, metallurgy and the engineering of oil in the '60's ( in that order of importance) than how much zddp was in the oils.
Z.