[rodnok01]

Hate to burst your bubble but in no way is that normal/good/to be expected. That looks like bearing material (thrust bearing if had to guess) and alot of it unfortunately. If that was leftover from engine work that'd be the worst cleanup and shop I'd seen. I just tore down a locked up motor didn't have chunks that big in it.

 

[rodnok01]

Tear the motor down before it grenades... Be prepared for alot of parts needed. If that's what came out of the pan imagine what's in the filter/pan and moving around the engine.
That entire motor would need to be gone through, checked and rebuilt.
It happens.... Won't take much debris to ruin cams, lifters anything oiled...

Anyone who said that's normal after a rebuild is 100% wrong and has zero idea what they are talking about. I've been rebuilding and blowing motors since the 70s and never seen anything like that and didn't destroy the motor in time.