Originally Posted by Dave63
I agree 100%, however, cars have flat tappets that the lifter wears to the cam lobe, where as HD's tappets are roller tappets. Much less friction. Still a wear pattern, but not as critical as flat tappets.
Are you guys running roller cams and lifters?
Most car makers went to roller lifters/cam followers in the mid `90s when the ZDDP was removed from auto motor oils.