If your truck has an axle flip and a drop shackle means the back is probably 7 or 8 inches lower than stock. You could flip the axle back on top of the leafs, that would lift it 6 inches in back. Or you could change the drop shackle for a stock or lift shackle, that might raise it anywhere from 2 to 3.5 inches depending.
You said you have Belltech parts on the front, but they don't make a drop control arm. They make a 2-inch drop spindle and drop springs (2 or 3 inch, but yours could have been cut for more drop). So you'll need stock spindles and springs. Check your control arms, the stock ones are cast, whereas aftermarket ones are fabricated from tubing and plate steel. So you can tell by looking if they've been changed.