I am rather new here , and don't have all the information yet, but I will share what I know thus far.
I have a 1964 comet hardtop (Mercury's version of a Falcon)
while it looks different, suspension,drivetrain,etc is almost identical to the same year mustangs.
While removing a 98 Explorer motor at a local yard... I took a look at the rear end.
8.8 rearend with 3.73 posi stock......disc brakes, with E-brake, factory "ladder" bars, pan-hard shock and even a decent sway bar set-up.
This rear end is 3" wider than my comet rear end , ( I believe the comet rear is 3/4" to 1" wider than a stang)
For me this is perfect as I plan to run late model rims.
I am awaiting new springs and a spring relocation kit before I try the install.....
I will take pics and if anyone is interested, I can share the info I learn as this might be a decent and inexpensive swap for you stang guys.....
I pulled the rear end myself (to avoid damage) rotor to rotor with e brake cables for $125.......
Andy