Check out this thread.
http://www.ls1truck.com/forums/front...ke-swap-8.html
It seems you can either swap the truck pulley onto the fbody pump or just pull it until it lines up. I hope this information helps as you are going with a slightly different setup with the LS2 pump.
2006 Superior Blue Trailblazer SS AWD, Stock as a rock
Sold: 2002 GMC Sportside Denali front end with a 2002 LS1, FLT level 5, Yank 2600, Trick Turbo, T76, Nelson intercooler, 60LB injectors, Warbro fuel pump, Eaton locker, Magnaflow, 3.42, Nelson Performance Tuning (speed density).
Sold: 1981 GMC LB RC 1500 2002 4.8L 4L60E 12 bolt 3.73 Richmond Lock Right AC PS Nelson Performance tuning