Your rings tried to contain the detonation that was hammering the tops of your pistons, they got hammered too.
Aluminum is pretty soft shit so imagine what your ring lands look like on the 'good' pistons being that some of your pistons the ring lands eroded as much as they did. They get hammered directly from the detonation and also from the reaction of the rings from that detonation.
Then think about the missing aluminum, where did it go just vanish? the rest of your oil system has aluminum rubble in it. I can probably dig up pics from my first ls with broken pistons, I just ran some kerosene through it and slapped some replacement slugs in it ghetto style anyway.
Then think of the detonation hammering on the top of your piston to do all that shit, where did that force go? It got translated through your rod and bearing to the thin film of oil that was supposed to keep the bearing from meeting the crank. It didn't and right now your top bearing on all your rods will be sloppier and different color from repeated slight contact with the crank during detonation. Sure they seem to work fine for now, but reference the earlier mentioned ls and I'll tell you it only lasted a few thousand beaten miles before it spun a rod bearing, now the crank and at least one rod is shot. Cost of future rebuild just jumped agian.
Get this new block and clean the fuck out of your head, oil lines, turbo, anything reused that sees oil pretty much. Then take your old block and forget about it for a while till you have a couple bucks or find more cheap parts. Replace a minimum of bearings, pistons and rings, and at least give it a hone. But a machine shop to check the bores and a basic hone is really not much money. Then you'll have a spare block that may have a fighting chance at doing more than just waisting your time.