Rear diff question

So I went to do the swap today and with some closer measurements it is the same width from back plate to back plate but the perches would have to be moved out 2" on each side and I would have to have the driveline shop here in town make a custom $50 u joint so I decided to sell this diff and buy this 73 dart for the 83/4 and front spindles because my dart has disc brakes with 4 piston calipers and small 5x4 bolt pattern and I can't find rotors little lone to fit with 5x4.5 bolt pattern. But thank you all for your input here are some photos of the 8" diff20170502_092846.jpg 20170502_092826.jpg 20170502_092817.jpg