I have always understood that the lifters have a symmetrical convex curve on the bottom that is surface hardened for better(longer) wear and the lobes of the cam are not at 90 to the sides but slope one direction to spin the lifters, also to prolong wear, as the cam doesnt rub the whole face of the lifter(less friction as well)Confirm? Deny? I wonder, if these are hardened surfaces, how you are expected to fix the cam they were supposed to repair themselves after you paid them to do it, by hand sanding hardened machined precision surfaces. Just Sayin'?