It will probably be less of a headache to go to a local off road shop, I found a shop in my town that cut the old perches off and welded new ones on where they fit the springs in my Dart for like $70 plus tax. That was parts and labor.
The shop can re-weld the spring perches onto the axle keeping the original pinion angle. Although, pinion angle does vary from car to car due to suspension height and stuff.
