I think 30 passes caused that damage.

Does your motor have the lifter galley oil modification that puts mote oil to the bearings?

We pulled a 360 down and the bearings look bad. Bearings 2, 4, and 5 don't even fit snugly into the main bearing cap anymore. They seem like they are egged. The lead overlay on number 5 bearing pretty much flaked out.

These bearings have about 30 passes on them.

What do you think the cause of this is? (see pics)...

1) How high did it get twisted???

2) How much temp did it see???

3) Oil???

Not enough clearance. Crank grinders like to grind your crank on high side, bearing manufacturer likes to give you bearing close to max wall thickness and old blocks main bores shrink from heat cycling. Now that it has bearings that look like these guaranteed main bores have shrunk. Probably needs line honed.

When you get crank turned have turned .011-.021-.031 US to give you more bearing clearance. Clevite now makes bearing in std with ex clearance so if you have a new or good std. crank use part # MS1266HGX

An engine with a little to much clearance will run forever, one a little to tight will die young.

I don't buy not enough clearance with damage that bad in only 30 passes on a mild build. I'd like to see all the bearings, rods and mains. What is "oil looks good"? It must have metal flakes in it, correct? What were the bearing clearances set at when it was built? Was it pre-lubed? What pressure was it running at? Why did you disassemble it in the first place? Internal noise? What does the oil pick-up screen look like? Are ALL the internal galley plugs correctly installed? A lot more investigation needs to be done before a proper diagnosis is made. Plenty of stock lower end 360's running around that stay together under quite a bit of abuse. Lets find the actual cause so there won't be a repeat.
Doug