I have a factory width 12 bolt in my 64 Chevelle I am considering having naroowed up about 4" - 5". It is a built unit with Moser axles, pro gears and spool. The catch is it has a ladder bar setup. So these brackets would have to be put back in proper location. And of course the axles will have to be re-splined or new ones ordered.
As everyone else, money is tight. So wanting someone thast is reasonable but does good work. Please email me if you or know someone interested.