It's a stock bore 6.0. This is the first time it's ever been opened up. About 65k miles I would guess. What all do you think I should replace?

BTW I'm not exactly sure what you were asking. If you were asking about something else, just let me know.

 

Just to let you know I have a set of stock LQ4 piston I will get rid of.

 

What is the proper ring gap? Or are the GM rings properly cut from the factory?

Should I buy a mic and measure the bore? If yes, what are the specifications for a stock piston?

In the first pic, are my pistons dirtier than normal? Do I need to use Seafoam to clean them?

What kind of break in process do I use for the new piston rings? The work starts tomorrow guys!

 

What ever happend with this deal? I replaced two pistons on my 6.0l, and swaped a few others to different holes. I found the new pistons were 6-8 grams heavier than the ones I was replacing, so I just lightend them. I got lucky it wasn't the other way around or I would have had to replace all 8. You don't want the new piston to be off more than 2-3 grams from the others, 4g max. That head should be ok, just smooth out the goudge with a cartrage roll, and do a light re surfac. Remember to clean everything really well, and be sure the head bolt holes are cleaned out.