piston questions

The last straw when I decided this motor was done at the time, was getting it home and drained the oil, and got a silver slurry out of it that I have never seen before.probably because of the stuck injectors.
That was towards the end of 2016, it would be 2019 before I touched it again, found a used one on CL to get the Durango mobile again. I put that motor on the stand to re gasket it before I put it in, found out those heads were cracked, so I pulled my new EQs off the doomed rebuild and that's when I discovered the bent exhaust valve on #4. So I had to send them off to the machine shop, and the doomed short block has been on a stand ever since.
And the machine shop said they'd seen engines that were dragged out of a field after 30 years that they didn't have to work so hard beating the valves out of compared to this set ... Remember. Ready to run right out of the box"...