Narrowing an 8 1/4" rear end, how is it done?

jcwren said
The biggest negative against this rear end is that it's currently a 5 x 4.25" bolt pattern, and the front is 5 x 4.5" (it has spindles, etc from a '73 with disc brakes). One option is to re-drill the axles, and there is someone local I found that can do it. It being a C-clip axle means there aren't any holes drilled in the stud plate, so the new bolt pattern can be drilled halfway between the old one. I do need to confirm the outside drum to drum measurement to make sure the wheels I want to run are available in whatever backspacing that turns out to be. And I would like to put discs on the rear.

In this case, I would seriously consider just going down to the local Pick 'n Pull and grab an 8.25 out of a Jeep Liberty... Why? Many already have 3.55+ gears in them, limited slip, and they already have disc brakes on them.
Width is a touch wide ~55 1/2" flange to flange if I remember correctly (the commonly used B body 8.75 is 54 15/16, so you're only about 1/4" wider than that per side). That can be made up for with offset wheels.
Pros? All the desireable equipment is already on/in the diff, ready to go. No additional cash outlay. (Especially a good deal on Half Price days at the PnP...!)
Cons? There's lots of unnecessary Jeep bracketry that will need to be cut off and properly spaced perches welded on at the correct pinion angle, but you'll probably have to end up doing that regardless of whatever rear you use. Additionally, depending on the year, it may have a flange-type pinion yoke that will need to be dealt with, either by replacing with a U joint yoke or using the driveshaft end adapter from the Jeep, possibly with an adapter U joint. And a little minor fab work getting the parking brake cables hooked up.