Maybe you should term it "narrowest available and useable 9" rear end"A 63-65 Fairlane, and pre 66 Mustang 9" housing is very scarce. Granada drum brake 9" is not much easier to find. Chances are you'll need to shorten a wider one and in that case the best one to use is 71-73 Mustang... available cheaper than earlier ones and has the 2 3/4" tube diameter where the U bolts need to be. You can use *" axles from a Granada or Maverick to make the rear 58" or 56" respectively.
While i'm on a roll (or rant?) here...
I've been doing this since i was about 16, to make money by selling them and for my own cars... i lost count how many times i've been offered "advice" on an easier way. Usually they say to start with a 1968-74 Econoline housing, the ones that are "real short" on one side and use two right side axles. I heard it again on Saturday when loading up more rear ends to shorten.
It's B.S. The rear is a mile wide and the offset is not that much, it's not that one side is short it's just that the other side is really,really long. As i am just about to cut one up let me measure...
(1/2 hr rolls by)
...OK, back. The whole housing without axles is a whopping 63 1/2" wide. Pinion center to the right side housing end is 27".
On a centered pinion 9" the left axle is 4" shorter than the right, using two right sides means a 2" offset to the right, pickups do this to clear the gas tank with the driveshaft, vans do this to give footwell room for the driver. On a car it'd mean widening the tranny tunnel or raising the car real high to clear the driveshaft.
So... using two right side axles gives us a 2" pinion offset and a housing that's 58" wide, put axles in that and it's 63"... stock width for a truck and wider than any Mustang or Fairlane.
[This message has been edited by TomP (edited 02-23-2004).]