Fox 2004 Cobra Terminator Rear Irs Upgrade Fox

69shocktower

Active Member
Nov 5, 2003
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For my 89 GT I just got a 2004 Cobra Terminator rear end with 4.10 gears in it for under $1k. The swap looks pretty easy. But measured and looks up to 2 inches wider. And probly need to upgrade brake master cylinder to 95 plus cobra. Any advice on wheel spacing to look normal and brake master cylinder upgrades appreciated. Thanks,
 
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Yeah, you'll need a cobra front brake setup and a master (or GT front brakes and associated master but might as well go cobra). You'll need correct springs, different brake lines, exhaust, and as for the rear wheels you'll need a 9" wide wheel with a 6.75 backspace and a 275 wide tire.

Details on my build here... Bird_dog0347 rescues a Fox - Ford Mustang Forums : Corral.net Mustang Forum and here....

Drivetrain - Picked Up A 04 Irs For My Fox, Have Some Questions. | Page 2 | Mustang Forums at StangNet



@RacEoHolic330 here... Build Thread - Want To Blow 4 Years And $40k On A Foxbody? Step By Step Instructions Inside! | Mustang Forums at StangNet
 
Yeah, you'll need a cobra front brake setup and a master (or GT front brakes and associated master but might as well go cobra). You'll need correct springs, different brake lines, exhaust, and as for the rear wheels you'll need a 9" wide wheel with a 6.75 backspace and a 275 wide tire.

Details on my build here... Bird_dog0347 rescues a Fox - Ford Mustang Forums : Corral.net Mustang Forum and here....

Drivetrain - Picked Up A 04 Irs For My Fox, Have Some Questions. | Page 2 | Mustang Forums at StangNet



@RacEoHolic330 here... Build Thread - Want To Blow 4 Years And $40k On A Foxbody? Step By Step Instructions Inside! | Mustang Forums at StangNet
How do you like the end result of having IRS in your car?
 
Hey man I've done it a few times. The 05 and up wheels look great on an IRS fox. Will have to use spacers in the front. You can grab 94 to 95 spindles and front control arms to help. The irs in a fox needs about 40mm backspacing. If on a budget pbr dual piston calipers work well with the matching master cylinder, booster, and proportioning valve. Brake line work is in order...fittings are different from fox. You'll need to take an emergency brake cable bracket from a 94 to 04 and matching cables. The flange on the IRS has to be changed to the straight axle flange (easy). The bump stops on the fox rear have to be removed. With my IRS I have no wheel hop with the stock bushings and (Monro) shocks. Had a budget 347...now have full built 331. Everyone told me the stock t5 driveshaft would fit....it does but the trans output seal rides pretty close to the yoke. I get my driveshafts shortened 1 to 1.5in depending on the set up. Any questions you have I'd be glad to help.
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