I am asking because I bought a fox rear axle I am converting to sn95 for a 67. I thought the were the same width exactly.
As has already been posted, the second post in the thread says the disk brake mounts cause the axles to be a little longer. The first post also shows an axle length difference of ~0.75" between the 86-93 axles and the 94-98 axles. If you are using Fox length axles and no disk brakes, then the overall width should be comparable to the 67-70 rear end.
From the second post:
Early Ranger rearends (1983 to 1992) have a driver side axle (the long side) that is the same length as a Fox body axle. That's the cheap way to do a 5 lug swap on a Fox, (two early Ranger driver side axles) ....
I bought the kit with axles brackets and lines to keep the stock fox width and go to a 5 lug cobra rear disc. The fellow there claimed that in most cases you don't need the antimoan brackets because the axle is pulled in shorter and there is less flex in the shaft.
I mocked up the brackets, axles, calipers and wheels and slid it under the car. The fit is great if not perfect for my boss 338 wheels.
So you could buy an 8.8 from a fox to SN95, buy this kit and the calipers and be good to go for a 67-?? mustang. Many fox guys buy the calipers rebuilt from autozone or oreillys and save even more than I did.
The trick is finding a good used rear with the gears you want. I want to point out it looked like my axles were used with some machine work on the hub end and new studs. I could be wrong about that but that is what it looked like to me.