[Batman]

Pace and Scoggins dickey have kits also, T/R is kinda high price wise. Other option is to take the list of parts from T/R and punch them in to GMpartsdirect. Keep in mind almost all the LS1 gaskets are re-useable (depending on condition of course) so be careful not to damage them. Also do an oil pump and timing chain if you have the cash, save you time in the future. Also do yourself a favor and get an ARP crank bolt so it can be re-used. Also definately DO NOT re-use the oil pump O-ring and be damn careful putting it in. I would also change the front main seal.

Re-Useable gaskets
Throttle body
Intake manifold
Valve covers (I'd buy new ones cause if they fall out they rarely go back in)
Timing cover
Cam retainer plate

Gaskets to definately replace
Water pump
Oil pump O-ring
Front main seal
EGR and AIR (if you still have it)