5.3 pushrod wear

[Joe406]

I have built quite a few SBC engines as well as old Pontiac engines. I see a common issue and I wonder if anyone has seen the same. On an old flat tappet cam the lobes are machined to allow the lifter to spin. Which in turn causes the pushrod to spin. I keep seeing bad wear on 5.3 engines I have taken apart. I assume when they designed the engine they accounted for this but I don't understand why I keep seeing this issue. Anyone have any ideas? What makes the pushrod rotate on the 5.3 to prevent wear? I will upload a picture tomorrow when I get back out to my shop.

 

[exp500]

I believe it is a lifter/pushrod issue- lifter always keeps pushrods tight so lubrication minimal, and the pushrod ends are softer than they should be.Top cup of lifter should be tapered but probably isn't. A heavier oil should cure that.
On flat tappets, cam lobe is tapered to keep cam against rear, no taper on roller cams. Lifter spin a bonus.