Swapping 8.8 (85-93 fox) into my 1980 Fairmont tech hlp plz

[quarterstang86]

Some of you may know, I purchased a 1980 Fairmont Futura off ebay, I-6, manual 4 speed od.

The rearend is having issues with only 38k on the car, I've had to take the passanger rear brake assembly completly off the car to drive it w/o grinding noise.

Is there anything technical besides the brake lines to swap in a 85-93 8.8 out of a mustang?

re: will the driveshaft bolt up etc?

[quarterstang86]

Some of you may know, I purchased a 1980 Fairmont Futura off ebay, I-6, manual 4 speed od.

The rearend is having issues with only 38k on the car, I've had to take the passanger rear brake assembly completly off the car to drive it w/o grinding noise.

Is there anything technical besides the brake lines to swap in a 85-93 8.8 out of a mustang?

re: will the driveshaft bolt up etc?

[Chuck W]

I've got a noisy 6 3/4" axle in mine as well, but it will be coming out soon also.

I "think" the comparion flange on the diff is different between the 6 3/4" and the 7.5/8.8's. Not a big deal to swap in another rear d/s flange though if need be.

Other than that, it is a direct swap (aside from the possible brake line issues, which are a minor thing)

[Chuck W]

I've got a noisy 6 3/4" axle in mine as well, but it will be coming out soon also.

I "think" the comparion flange on the diff is different between the 6 3/4" and the 7.5/8.8's. Not a big deal to swap in another rear d/s flange though if need be.

Other than that, it is a direct swap (aside from the possible brake line issues, which are a minor thing)

[FoxChassis]

...a 85-93 8.8 out of a mustang?
That should be '86-'93. The '85 model year still had a 7.5" rear.

Just so you don't buy a rear from an '85 model, thinking that it's an 8.8" unit.

[FoxChassis]

...a 85-93 8.8 out of a mustang?
That should be '86-'93. The '85 model year still had a 7.5" rear.

Just so you don't buy a rear from an '85 model, thinking that it's an 8.8" unit.

[Marz]

Also, while you still have that 8.8" out... why not upgrade to Fairmont/zephyr (or any FOX based wagon) 10" rear drum brakes? You can used the stock master cylinder and wont have anyproblems. Just be sure to grab all the 10" drum hardware (10" drum backing plates included), get new 10" drum wheel cylinders and grab the 10" hard brake lines that attach to the axle.

They did great on my exFutura... and would like to do it to my GT. It's a good cheap brake upgrade.

[Marz]

Also, while you still have that 8.8" out... why not upgrade to Fairmont/zephyr (or any FOX based wagon) 10" rear drum brakes? You can used the stock master cylinder and wont have anyproblems. Just be sure to grab all the 10" drum hardware (10" drum backing plates included), get new 10" drum wheel cylinders and grab the 10" hard brake lines that attach to the axle.

They did great on my exFutura... and would like to do it to my GT. It's a good cheap brake upgrade.

[paul78zephyr]

The late Fox 8.8 is a direct bolt in and a great driveline upgrade. I put a 1993 8.8" rear into my 1978 Mercury Zephyr (see my sig). The driveshaft bolted right up with no problems, although I was swapping from a 7.5". The brake lines are layed out a bit differently on the late 8.8" than on the 7.5" but mostly this was done by Ford to relocate the brake like connection to the rear flex hose closer to the axle center section to clear the dual exhaust. Your stock emergency brake cables should bolt right up to the 8.8s brakes.

If you are going to swap to an 8.8" rear I highly recommend that you choose your rear axle ratio according to the perforamance and/or type of driving you do. If you are looking for performance now is a great time to look for an 8.8" with a 3.27:1 (faily common in 5.0L Fox Mustangs with AOD), 3.55:1,, or even 3.73:1. These latter ratios will need to come from T-Bird TCs and are a 1/2" wider per side than the stock Mustang and F/Z axle. I would also recommend that you replace the stock Fairmont upper and lower rear contol arms and at least use the heavier duty stock 5.0L Mustang pieces. You may find it 'difficult' to remove the bolts/nuts that hold the old control arms to the unibody as they get pretty rusty/seized under there after 20+ years. I had to heat mine with a torch (fuel tank removed) and then hit them with a 600 ft-lb impact wrench. I think I still had to grind off one of the nuts with a cutoff tool.

Good luck,
Paul78Zephyr

[paul78zephyr]

The late Fox 8.8 is a direct bolt in and a great driveline upgrade. I put a 1993 8.8" rear into my 1978 Mercury Zephyr (see my sig). The driveshaft bolted right up with no problems, although I was swapping from a 7.5". The brake lines are layed out a bit differently on the late 8.8" than on the 7.5" but mostly this was done by Ford to relocate the brake like connection to the rear flex hose closer to the axle center section to clear the dual exhaust. Your stock emergency brake cables should bolt right up to the 8.8s brakes.

If you are going to swap to an 8.8" rear I highly recommend that you choose your rear axle ratio according to the perforamance and/or type of driving you do. If you are looking for performance now is a great time to look for an 8.8" with a 3.27:1 (faily common in 5.0L Fox Mustangs with AOD), 3.55:1,, or even 3.73:1. These latter ratios will need to come from T-Bird TCs and are a 1/2" wider per side than the stock Mustang and F/Z axle. I would also recommend that you replace the stock Fairmont upper and lower rear contol arms and at least use the heavier duty stock 5.0L Mustang pieces. You may find it 'difficult' to remove the bolts/nuts that hold the old control arms to the unibody as they get pretty rusty/seized under there after 20+ years. I had to heat mine with a torch (fuel tank removed) and then hit them with a 600 ft-lb impact wrench. I think I still had to grind off one of the nuts with a cutoff tool.

Good luck,
Paul78Zephyr

[Dean_T]

Paul has a good point. My '78 Friggin' Futura trans has a .5 OD gear which is useless with a 3.55 rear. I may have to step up to 4.30 at least.

Oh, You can reuse your Fairmont e-brake cables and I recommend using the later lower shock mounts and buying new shocks to fit ('87-'93 Mustang is a safe bet - brand is up to you).

Dean T