a couple of threads for info...you may have to register to see the pics...seems that a 2" body lift will clear the cab and the tranny/transfer case combo...or you can take the high hump, unbolt it, slide it over the low hump, mark it, cut the hole 1 1/4" - 1 1/2" smaller and then screw the high hump down using sealant between the two...
http://forum.73-87chevytrucks.com/sm...?topic=14052.0
http://forum.73-87chevytrucks.com/sm...p?topic=5766.0
http://forum.73-87chevytrucks.com/sm...p?topic=4609.0
http://forum.73-87chevytrucks.com/sm...?topic=11798.0
http://forum.73-87chevytrucks.com/sm...hp?topic=11838