H/C swap...whats needed??
1. Headgaskets (can I re-use the stock ones?)
2. Intake gaskets
3. Hardend pushrods
4. ??
5. ??
I cant think of what else I need
1-H/C gasket kit (head, water pump, timing cover, O-ring, Pulley bolt, front seal)
2-Heads
3-Cam
4-p-rods (size depends on mill amount on heads)
5-Lifters, (CRANE or Comp Cam 850-16)
6-Rockers (I would send yours to NASTY's for a c-clip update from Harland ~$200)
7-Intake (LS6 or FAST 90/90)
Just FYI, when you ask a Q like that list all your existing mods (bolt ons), it helps us in advising.
1. Get an expandable pen magnet. You'll use it a gazillion times!
2. Get ready for a fluids (coolant, oil, PS fluid) mess. Oil Dry and a couple of old blankets will keep things clean.
3. Label everything. Put each set of hardware (e.g. the timing cover bolts, intake bolts, etc...) in its own baggy and place a piece of paper in it with it's name. It makes re-assembly so much easier.
4. Get a set of metric "ratchet" wrenches. You know, the kind that you put over the nut or bolt and ratchet back and forth.
5. Make sure you need 8MM, 10MM, 13MM, 15MM, 18MM of both regular socket, deep-well socket, wrenches, and ratchet wrenches. You will need a 1/2" drive, 24MM 6-point socket for the crank bolt.
6. You will need a 3' breaker bar (1/2" drive), a small torque wrench and a large 1/2" drive torque wrench.
7. A 3-prong pulley puller for the crank pulley.
8. Get the complete H/C gasket and bolt set from Texas-Speed. It has everything you will need. YOU CANNOT REUSE YOUR HEAD GASKETS!
9. Get a degree kit and dial indicator (see Snap-On website). Make sure you get a dial-indicator extension. You should measure everything, including your ACTUAL preload.
10. I don't know your setup, but if you are running tight compression (i.e. had the heads milled), check PTV clearance. Make sure the cam matches the cam card by degreeing it (even if you use a non-adjustable timing gear, you still want to check).
11. Learn as much as you can beforehand about, PTV clearance, valvetrain geometry, preload, etc. It's better to have this knowledge BEFORE you put it back together than to find out afterwards, you may have screwed something up.
12. Since you're a newbie (like I was), the chances of you making a mistake are pretty good. Get the ARP head studs in case you have to take the heads back off again. The cost of the studs is roughly the same as two sets of GM head bolts.
13. Take your time. Don't do any shortcuts because they will always bite you in the a**. You will run into a lot of small headaches, so be calm, take your time and attack each one with some thought.
There's lots more. Print out the directions on http://www.ls1howto.com and follow them EXACTLY.
Good Luck!
1 hardened pushrods (85.00)
2 New GM head gaskets (49.00)
3 new GM head Bolts (40.00)
4 New GM Crank bolt (5.00)
You should be able to reuse everything else unless your car is a 98. Then you may need to do the water pump gaskets. I have done this on my personal car many times

The only things I couldnt think of were the head bolts and the water pump gasket...
Byter...I really appreciate the in depth write-up
...luckily I have someone doing ths swap for me, and he has done alot of them...I was just making up my own list soo I could double check I have everything ready for him when the car goes to his house. 
