HOT UPDATE!!!
The mechanic called me an hour ago. He said:
#7 piston has hole in it. # 5 piston has dings in it. Cylinders have scratches. Passenger side head is shot with broke valve. He said it looks like #7 piston valve made its way to #5 piston.
I asked him if the head gaskets were put on backwards, he said no. He said he has no idea what caused the engine to fail. He said he doesn't want to go to court. He said he is going to do the following free of charge:
Replace #7, #5 pistons, replace ALL piston rings, hone entire block, replace passenger side head, replace all valves (both sides), replace bearings (crank shaft?) and give me a warrenty on the whole motor.
Questions: Should I have him do anything else (on my dime) while he is in there??? Please advise. Ie.. oil pump, water pump? (139K miles)
I get all parts back except passenger head (core)
Sounds like he knows he screwed up but won't admit it. But I got to tell you... I don't care! as long as my truck is getting a rebuilt engine that may last 300k miles. BTW, he has had my truck since Sept 28th and I only put 300 miles on it after the HG change.
Thank you everyone for your imputs. Too late to get the truck "out of there". I have to roll the dice again and hope his work improves.