[olddog]

It looks to me like the rocker had twisted side ways, the pushrod was out of the pocket, and the roller was no longer on the valve. It appears like it twisted both directions. If the beat up area on the edge of the roller tip and the beat up area beside the pocket line up with the pivot point, then I'm sure of it.

I didn't see any bend on the push-rod, at first glance, but pictures are 2 dimensional. Is this push-rod 0.200" shorter than the others? I would want to prove that the push-rod explains all of the slop.

Maybe the side pipes are too loud, maybe your hearing is not perfect, but that should have made a lot of noise for a long time. Not judging here. I just think this happened over a longer time period than you are thinking.

The worst thing is getting all the metal shavings cleaned up. If only someone would invent an aluminum magnet.