I've just done mine and there isn't much to it really.
However, are you sure your head gasket has blown? Have you done a compression and/or leakdown tests? The oe gaskets are a pretty good gasket and do make a decent seal. Mine were great after 368,000Ks and only came off due to a burnt an exhaust valve. (Intake gasket ruptured causing an over-heat.)
I used GM head gaskets (24503479 & 3480), cleaned the surfaces, used GM sealer on the studs into the block (the Loctite 567 is also a good alternative) and then torqued them up. Easy.
GM head bolts are torque-to-yield, so you must replace and not reuse the ones that come off. GM charge a hellish price for these (list is $254+tax for all 16) and rather than buy the el-cheapo Chinese crap for ~$50, I bought USA made ARP studs for ~$150. ARP 193-4001 for hex or 4002 for 12pt (Rocket industries are $130 plus post.)
ARP studs, are re-useable, the heads will drop on over them in the car, and studs clamp better than bolts.
Booran Holden in Dandenong Vic have the revised intake gasket sets (89017825) in stock for $165 incl tax but plus postage, as opposed to the GM list of $190+tax.
Get the heads properly checked out but you may find the valves have recessed a lot in the seats and a change-over may be a better option than throw money at yours. Make sure you get supercharged heads as the Ecotec heads are different. I got mine complete with hardened seats for $660. Having your existing heads fully reconditioned will be about the same $$ anyway, but you'll wait for them to get done.
TopTorque in Nunawading Vic may have a pair on the shelf ready to go.
All up my top end rebuild cost ~$1400 for everything including oil, filters, coolant, gaskets & seals..
