Chad, if truck manifolds are used the A/C must be removed. Most people try to stay away from the truck manifold kits due to that reason. On any turbo kit where the turbo is mounted directly infront of the motor you will have to remove the stock fan and get a pusher fan.
Here are some pictures of the APS twin kit where the A/C can remain
http://www.ls1speed.com/xx_fbodysupercar.cfm?KeepThis=true&TB_iframe=true&height=500&width=600
Here are pictures and information on the truck manifold kits
http://kentuckyturboandperformance.com/photos.html
This is a great read for truck manifolds
http://www.ls1tech.com/forums/forced-induction/1303972-how-diy-build-truck-manifold-kit.html
This guy has two different setups in his build thread
http://www.ls1tech.com/forums/forced-induction/1215551-98-camaro-370ci-t76-build-up.html