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

Are you sure that one of the local pull a part type yards don't have an A-body 8.25? They are fairly common in '73-6 A bodies.
I'll have to start hunting around. We moved about 45 miles north a couple years ago, and there's a bunch of interesting looking junk yards I haven't been to in this area.