That is the Dana 44 with the large hubs isn't it? I ran one in a jeep with 38.5 boggers and a 406, beat on it hard and couldn't break it. However I was not running the weight you are. Ditch the 44, 208. Add a Dana 60 front, np 205 or doubler. Get some beef as far as TIRES! Run 5.13-5.38's and definitely go with disc brakes all around! Hope this helps. Love the Blazers!