I have a 5 lug conversion on my 88 Bird with 17x8 Bullitt Wheels on it. I believe the Diff is from a Ranger. It's very narrow. the Wheel Offset barely clears the quad shocks, but I have a ton of room on the outside. I would like to get wider Bullitt Wheels for the rear. How wide of a wheel can I fit? What Backspacing do I need?
I used a 10" wide with 6.5" bs and a 1/4" spacer each side. That was about the max with 9" slicks. The wheel wells are very full. Your street tires will not have as much side wall or height, but I have the same fox mustang narrow issue you have.
Sweet. I'd like to run Drag Radials on it. 28 inches tall or more. I will roll the fenders an whatever else to get them to fit if I have to.
Measure how far out you can move them, and then get some decent quality bolt-on wheel spacers. The stock wheels on my 88 TC had the tucked under look, which was the one thing that always bugged me about the cars ... so I bought some 1" spacers off eBay, looks way better now, wheels are where they should have been from the factory.
On yours, from the photos I'm guessing that you could use probably 1-1/4" of spacer.
cheers
Ed