Quote Originally Posted by PaulE View Post
Thinking about installing a 8.8 rear end in my '37 Ford, looking for the flange to flange width for a 1989 Mustang rear end. Have searched the internet but can't come up with the answer.
Anyone know the width?
Paul
Hey Paul,
According to this article in CarCraft magazine "we discovered that the Fox-body Mustang 8.8 rear is a mere 31/48-inch wider than the stock 8-inch '67 Mustang rear."

Read more: The Ford 8.8 Mustang Rear End - Car Craft MagazineThe Ford 8.8 Mustang Rear End - Car Craft Magazine
Most places list the '67 Mustang rear at 59.25" so the '89 Mustang rear should be right at 59.90" from each wheel mounting surface. That should work depending on the backspacing of the rear wheels you intend to use.
Hope that helps.
Randy