[Captainfab]

If you change the front suspension, crossmember and all, you will have to drill 1 hole on each side, and elongate 1 hole on each side. As for the differential, I would recommend keeping your original 12 bolt and have that narrowed. The 8.5" 10 bolt is a decent differential, and will hold up to a good bit of abuse, but I see no reason to not use the 12 bolt that you already have. The main difference between the two is the size of the ring gear, 8.5" versus 8.875" for the 12 bolt, and the axle splines and possible the axle diameter. The 12 bolt will already have the trailing arm mounts and the panhard bar mount, so you won't have to have those transfered to the 10 bolt, which will save some $$. You're already going to have to purchase custom length axles, so you can order them with the 5x5 wheel stud pattern.