What kind of trans did the truck have prior to the swap?
What kind of mounts are you using for the LS? Did you have to move the trans crossmember back or?
Depending on the answers above you may need to have a new driveshaft built. Did the rear fit?
Any parts store should be able to get you an aluminum radiator that fits, it just depends on your budget.
How are you going to run the exhaust? 3/4 length headers work on 4x4's...
As for the shifter, again what kind of trans was in it?