[Captainfab]

I wouldn't waste any money on that Eaton HO52/72. For one, you can not do what you are wanting to do with it. You will be far ahead to find a '71-'82 12 bolt or a '79-'87 10 bolt. Of course the '71-'72 will basically bolt in. The '73+ will require some cutting and welding to bolt into your truck. I make the trailing arm mounts, and you can cut the panhard bar mount from the Eaton and weld to the new differential. You could also use a '64-'70 12 bolt and install the 5 lug conversion axles. The '70 and earlier differentials are 1.5" narrower than the '71 and up. And of course you will have to install the posi carrier and gears that you want in which ever differential you go with. The chances of finding a differential already with a posi is somewhat slim.