Rear End Swap?

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I may be wrong, but I think the T-bird rear is a different width. I think this would be a very popular swap otherwise. I believe that if there is any way to perform a "simple" rearend swap, it must be from similar generation Mustangs. If you are good with a metal band saw, plasma cutter, and a welder, you can modify any 8.8" or 9" housing, but you still have to obtain the proper length axles.

Needless to say, 99% of the time, most will take it to a shop and have a new gear set installed. Parts and labor is generally $500 (plus/minus) depending upon what else needs to be done (traction-lock rebuild, axle bearings, etc.)
The best gear bang for the buck is the 87-88 Turbocoupe rear ends. I got my 87 Turbocoupe rear end from the local Pick a Part for $60.... that was for the housing, axles, gears, all the internal parts. The housings are the exact same size as the 86-98 Mustang 8.8 housings. The only difference is the quad shock holes are higher on the bracket, and you just have to drill new ones lower.

Basically the complete rear end is wider, but it is just in the axles and brake brackets. You can swap the axles and drum brakes onto the TC housing and it will all fit perfectly.

Since I used 5 lug axles and disc brakes, I sold my stock rear end to a friend for $ I basically got 3.73 gears installed for $20 and several hours of my time!

Here is some info on it, including the rear disc swap:

Of course, it all depends on what you can find locally. Might check for parts, you might get lucky!

Oh, and if you do pull the gears.....plan on having them installed professionally or they will more than likely not be installed correctly and will whine and possibly fail.... so keep that in mind. That is one reason I swapped the complete rear end housing.
Do the 87-88 Tbird Turbo Coupe as suggested above.
Been there and done that! With success! :nice:

Auto trans Turbo Coupes come with 3.73 gears and manual Turbo Coupes come with 3.55 gears. I choose 3.55 since I do more highway driving.
It takes 2 guys the first day to get the old rear end out and the new one bolted in place. It takes 1 guy another whole day to do the brakes.

You will need a several sets of fittings, I recommend that you get them from Matt90GT's website, Read Matt's instructions thoroughly, everything you need to know about the brakes is all there. You need to be patient and follow all the internal links, and there are many of them. You will need 2 fittings in the rear to adapt your old brake tubing to the TC disk brakes. The fittings go between the steel tube and the caliper brake hose. You will need another set of fittings to make a 2 port to 3 port adapter. To make life simpler, just buy the kits from Matt. You could piece them together, but it's not worth the time unless you work at an auto parts store with all the fittings ever made. You will need to drill the quad shock mounting holes 2” below the holes drilled for the Turbo Coupe mounting points. The bolts are metric, so don’t loose them or the nuts. A 15/32” drill should be about the right size unless you have access to metric sized drill bits. Going without quad shocks is not an option unless you have aftermarket parts to soak up the wheel hop.

You will need a proportioning valve, Summit has one for $40 + shipping.
You will need a kit (FMS makes the part) to gut the stock proportioning valve, Summit also has that, about $10.

You will need a new master cylinder, see Matt's site and make you choice. I used a 94-95 Mustang master cylinder. Note that rebuilt 94-95 Mustang master cylinders do not come with a reservoir. That means a trip to the junkyard and some more money spent.
Your brake pedal may be very hard and almost impossible to lock up the brakes. I had to replace the front calipers with 73 mm calipers from a 91 Lincoln Mark 8 to get the braking performance up to par.

See for help with the emergency brake. The ebrake handle on 87 and later models must be modified by removing the spring, and tack welding the pawl and ratchet assembly.

Bleeding the brakes will require 2 people and some coordinated effort. I don’t recommend using you wife or girlfriend to pump the pedal – they get offended when you yell at them. I used a homemade power brake bleeder constructed from a garden sprayer and some fittings from Home Depot. It cost about $25 and was worth every penny.

All in all I have been very pleased with the results.