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Junior Charter Member
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Discussion Starter · #1 ·
I did a quick search and could not really find anthing on this. I have access to an IRS set up from a Merc Cougar. Is it the same as the T bird SC? If not, should I steer clear of it or can I use it?
 

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FFCobra Fanatic
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This is the list of donor vehicles from the FFR page on IRS:

Donor Vehicles

1989-1997 Thunderbird Super Coupe (All Posi-traction)



1992-1997 Thunderbird V-8 models with rear disc brakes (some posi-traction)



1992-1997 Lincoln Mark VIII (All aluminum carrier, most non-posi-traction)



1989-1992 Mercury Cougar XR-7, supercharged V-6 (All posi-traction)



1993-1997 Mercury Cougar V-8 with rear disc brakes (some posi-traction), after 94 all Cougars were called XR-7’s


Darren
 

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It depends on the year. Check the FFR website, they specify which ones will work.
HTH
Chris
 

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I used the rear from an '89 Cougar XR7. The XR7 uses the same rear as a TBird SC
 

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Discussion Starter · #6 ·
Thanks guys. The Cougar is in my Dad's salvage yard so the price of the rear end will be right. I will have to check the year model and see if it is posi trac or not.
 

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FFCobra Fanatic
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Don't trust just the year for the posi.

Do the wheel test to see if it really does.
 

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Discussion Starter · #8 ·
I hate to bug you guys but I will admit I am a GM guy with the exception of a 289 67 Cougar I built 25 years ago.

I called my Dad about the Cougar in his salvage yard and he said it was a Supercharged V6 5 speed car. The engine and trans are gone but the IRS is still there. My guess is it is a posi set up with some decent gears. He also has at least one more cougar and 2 or 3 T birds. I will be there this weekend to do some research. Any advise on what and where I should be looking on the IRS to help Identify it or will the VIN # help me any?

One last ?. I e mailed FFR but have not heard from them. How much does it add to your kit to have it prepared for an IRS? I found the price on the form but I am assuming this includes the IRS set up which I do not think I will need.

Thanks for your help on this.
 

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The IRS option does not include the carrier, axles or spindles/brakes. Includes subframe, upper/lower control arms, shock/springs, axles only(no cv joints).
 

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Discussion Starter · #10 ·
So even if I was using the IRS set up, I am still looking at an additional $2500.00? If this is true, for budget purposes, I will have to stick with the solid axle.

Thanks
 

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$1950 for standard width option, $2450 for pin drive option plus the cost of the donor parts which usally is $200+. Then the parts you would want to replace like calipers, rotors, redrilling hubs for 5 on 4 1/2" etc, ect.
Solid axle is much cheaper, but the IRS is real nice and resale you wont loose.
 

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FFCobra Fanatic
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Convincor is correct.
 

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I did the IRS and costs for doing were as follows. The rear makes it more authentic, rides better, handels better, but costs more. It's a choice we all make but this was a must for me.

1). FFR IRS option free due to superbowl discount.
2). Complete IRS from wrecking yard. $250.
30. Replaced all rubber bushings with urethane website vendor (cont think of his name but others can chime in) also new hub bearings and re drilled hubs to 4.5" total $300.
3). Rebuilt calipers $70 ea. total $140.
4). New rotors $80.
5). 1 new outter bearing for diff ($14) and both axle seals ($20) total $34.
6). The gears (3.27:1)other bearings and clutch discs did not need replacement.
Total rear end cost including brakes was $804. Will I get it back if I sell, probably yes. Would I do it again, yes.
 
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