cheapest/easiest 8.8 rear swap

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87National

G-Body Guru
Apr 15, 2009
661
679
93
eastern SD
I'd like to swap the 7.5 rear for an 8.8 in my 87 monte ss. What is the easiest/lowest cost method to accomplish the job? I'm ok with dealing with the Ford bolt pattern and stock gears (I do want to find a factory posi rear).

should I get a Fox body rear or 94-98 rear?......I understand the Fox rear is 4 lug/drum brakes.....while the 94-98 is wider than the gbody...which is the better trade-off?

I see many are using the quick chassis kit:
http://www.trickchassis.com/index.p...swap-instant-center-correction-kit&Itemid=320

What is required to be purchased in addition to the kit? I believe that mustang adjustable uppers.....and gbody lowers will work.....what else?
 

LS WAGON

Not-quite-so-new-guy
Jun 10, 2016
20
5
8
Bucyrus, Ohio
I put a Fox body in my wagon. It was like it was made for it. I used Trick Chassis uppers & lower adj. arms, The lower stock lower arms are narrower than the mustang lowers so you will need to put spacers in to take up the gap. I also replaced my drive shaft although you can just change the rear u-joint. If your working on a budget as most of us are, you can deal with the 4 lug axles until you want to replace them. I eventually changed mine with a set of Moser 5 lug. You will need to make or reuse your spring perches. Rear brake hose is in the same location. My concern with the wider diff. was tire clearance and correct wheel backspacing. I'm sure there are some guys here that can shed more light on the later model diff.
 
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marcar1993

G-Body Guru
Aug 31, 2007
702
209
43
New Jersey
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ostrich

Master Mechanic
Aug 27, 2012
310
313
63
Ontario, Canada
Guys,
I just finished this in my 85SS. Pretty easy swap considering what you get. Started with a 95 SN95 rear end. Wanted it for the brakes, and thought 1" wider would work (it didn't, wheel tire selection). Got Trick Chassis upper control arms and weld on spring perches (old ones, more work than the cost of the new perches). I put things together, but my wheels stuck out 3/4" and I didn't like the look, and wanted to keep the ZQ8 S10 rims with 4.5" backspace. I ended up calling Moser for a pair of Fox body (pre 94) 28 spline axles with 5 bolt Chevy pattern on the end. I also had to get the center hole of the rims lathed out because of the Ford axles. I upgraded the brakes to Cobra 11.65 rotors (not needed), just drilled out the rotors to match the Chevy bolt pattern, the rotors are hub-centric so just did it on my drill press. Used Energy suspension upper urethane bushings, UMI F-Body lower control arms (same length as G-body but cheaper), drilled them out for the rear sway bar mounting. Extras were 3.73 gears, rebuilt the posi with clutch packs and a new Cobra R diff cover. I have approx $1200-1300 in it. You can do it for less, but I upgraded a few things as I went. Don't be scared of this swap, probably on of the easier swaps I've done. Let me know if you need part numbers etc.
IMG_20160725_193813[1].jpg IMG_20160724_132625[1].jpg
 
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454GrandPrix

Master Mechanic
Jul 27, 2016
429
818
93
Lehi, Utah
I am also just finishing this swap on my 80GP. I went with a Fox body axle. I had to spend a little more money as I didn't find an axle close to me; that alone was $400 shipped from an out-of-state junkyard. I bought the Trick Chassis kit including new spring perches and adjustable lower control arms, then I had a local friend perform the welding for me. After that, I trailered it to my work (a dealership) and had my suspension tech properly straighten the axle, set the pinion angle, and perform a full alignment. I am still running the stock Ford 3.08 gears and axles; I found a set of clean Fox Mustang LX 'phone dial' wheels for pocket change (literally!) and am running those for now. My total investment at this point is $1500.

At first, I tried using my car's stock lower control arms. While technically you can use them with this swap, you probably won't want to--they push the axle about an inch rearward, causing your tire to be noticeably not in the center of the wheelwell:

13450814_937318713033439_598369477705868568_n.jpg


As soon as I noticed that, I picked up the phone and made another call to Trick Chassis to order some adjustable lower arms.

As for the driveshaft, a local friend gave me a Ford flange that attached to my stock driveshaft via a u-joint. It bolted right to the 8.8 axle, of course. No other driveshaft mods were required.

For the hydraulic brake lines, I bought a new rubber line (stock replacement) for the car. The rubber hose was way too short to mount the T on top of the diff where the Ford T sat, so I used a long bolt (with surplus nuts as spacers) and attached it to the lower left side of the 8.8 diff housing. I simply re-bent my left hard line to attach to the newly-located T. The right hard line wouldn't reach; I attached a brass coupler to my stock fitting, then I added a 12" extension line and bent it over the diff housing to attach it to the relocated T. Easy.


I will echo what others have said: when factoring in budgetary concerns, this is one of the best axle swaps you can do. Had I found an axle locally (and if I had any welding experience), I could easily be where I am for under a grand. That's not a bad deal.
 
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ostrich

Master Mechanic
Aug 27, 2012
310
313
63
Ontario, Canada
454GrandPrix, just working on the brake lines as well. I ordered a new center flex line and like you found it to be too short for the 8.8 mounting location. I think I found another one that will work from an 85 Astro van (Dorman H38261 ). waiting to get it in to try. Its 3" longer than stock with the same fittings. Have to get the car back on its wheels to check to see where the tire lands in the wheel well. Hopefully in the center, but good to know about the control arms.
 

marcar1993

G-Body Guru
Aug 31, 2007
702
209
43
New Jersey
On my car the stock lower arms totally set up the rear in the right spot, just about center in the wells from what I can see.

As for the brake lines, I got a 97 rear, so it had rubber lines from the calipers to the frame on each side. I got a set of 94 lines which are rubber but went to a central T like the stock G body one. I then made up some lines to the factory g body line, and mine too was too short to bolt right to the housing. I made a ~1.5" C out of sheet metal, bolted it to the axle, bolted the line to the top of the C, its the perfect spacer.
 

454GrandPrix

Master Mechanic
Jul 27, 2016
429
818
93
Lehi, Utah
On my car the stock lower arms totally set up the rear in the right spot, just about center in the wells from what I can see.

Hmm. Maybe your SN95 axle has control arm mounts which are in a slightly different position than the ones on my '89 Fox axle? At any rate, I tried it with my stock lower arms before spending the money on the adjustable ones. Oh, well.
 

marcar1993

G-Body Guru
Aug 31, 2007
702
209
43
New Jersey
No, the mounts are the same, people swap sn95 axles into fox bodies all the time. Dumb luck in your case perhaps? I've never heard of anyone else having that issue, but I believe you that you did... odd for sure.
 

ostrich

Master Mechanic
Aug 27, 2012
310
313
63
Ontario, Canada
Just dropped the car on it's wheels on the weekend. The tires center pretty good in the wheel wells. Any one figured out the rear sway bar? I set the stock one in, but doesn't look like it will work anymore on the control arms. Did you use an aftermarket one that mounts to the car, not the control arms?
 
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