@Rotto, your silence tells me you have discovered how much it will cost for repairs. I was shocked too but more pissed off. I just bought truck back in May. All stock and only 158k kilometres on it. Lots of opinions and suggestions on here for repairs.
I personally went with ARP studs instead of head bolts even though I was keeping it stock. Three mechanics I talked to recommended them. Also recommended was a water pump change. Good luck in your repair. I should have mine back this week.
2013 Sierra SLE 2500HD Crew Cab