Wow, sad to see this. Makes me wonder though how long ago you lost the electrode on the number 8 plug. If you were running around on 7 cylinders for a while your 02's would of been pulling fuel on all the other cylinders causing you to run lean, somewhat explaining the condition of a few of the other cylinders but also looks like you were having problems before all that.
Those pistons were forged as well no? That crack in number 8 makes me believe you were having massive and consistent detonating if it did that to a forged piston. So I think your theory on bad knock sensors would prove to be at least in part accurate.

 

If it busted an electrode and was running on 7 cyl I doubt he would have been driving the truck.

 

sorry to see this happen, this is by far my favorite motor (watched the videos over and over, cant get enough of that sound from the blowers!) good luck on repairs and preventing them in the future

 

I have don't away with all pcv on my engine...running pass side valve covers on both sides with metco oil fill neck breathers on top of short necks. Might be a good option for your beast.

 

Here's another pic of #8 after wiping it down better - droplets were just coolant. The 2 stressed areas are actually protruding humps relative to the rest of the piston face - haven't got to the bottom end yet.


Some pics of Bank 1 cylinders and head. Wiseco forged pistons appear to be intact.




Found this debris in the top side of the bank 1 head:

 

Expired valve seals?

 

Sure looks like a seal spring.

 

Put the knock sensors on the back of the head

 

That sucks to see hope you can get it fixed and running again...

 

Would have been a lot closer to where I needed it!