If you are doing it yourself, the a-body boxes for slant six cars used a bushing instead of a bearing. If the bushing is worn, it doesn't seem to be an easy DIY. FF can and does remachine them to take a bearing if the bushing is worn.

Otherwise, rebuilding didn't seem to be a big deal. I had one of mine apart last year. Used a spring loaded scale hooked to a wrench to measure the torque since its below what most torque wrenches will do. Just take your time and the shop manual is pretty good.