RE: Ring and Pinion
As long as you're reusing the stock gears, just replace the bearings yourself. Pull the wheels off and if you have drum brakes take the drum off and push the axle in. Pull off the rear diff cover and then take out the c-clip out of the carrier and then you can pull the axle out. Once the axles are out, mark the caps to so you can put them back where they came from. Unbolt them and then pull the ring gear and carrier out and then take it to a machine shop to get the old bearings pressed out and put new ones in. If you're going to replace the pinion bearings, use a pipe wrench to hold the pinion and then losen the nut and pull out the pinion gear. You'll have to use a brass floating punch to remove the old bearing races from the housing. Then again take the pinion to a machine shop to swap out the bearings using the same amount of shims that came out.
It's better to burn out than to fade away.