Re-using Used Lifters on Another Cam

I don't believe the theory that putting a 'crown' or spherical radius on the end of a lifter will make a lifter rotate. If anything, it will prevent it from rotating. The straight profile of a camshaft lobe will simply slide over the highest point of the crown [the center of the lifter]. This would exert the least amount of rotating force on the lifter.

However, lifters do turn. I've taken out lifters from late 1960's Chevy 307 motors and they looked like the inside of a mixing bowl. The Mopar ones look a dinner plate. [A rare occurrence].
To make those shapes they have to rotate. And this happens long after the 'crown' has disappeared.

There has been many discussions of poor results of changing camshafts due to lobe and lifter wear. The opinions generally claim it is caused by the quality of the metal and the heat treating process. This seems to have gotten worse in the last decade or two. Some camshaft manufacturers are buying Chinese Charley blanks and finish grinding them here --- or--- having them totally finished there.

Another issue is heat treatment. Nitriding costs money. It is a time thing. The longer it stays in the oven, the deeper the case hardness goes. But, 2 days in the oven costs a lot more money than 2 hours in the oven. So...…….