Which independant rear is everyone using?

[Rkloehn]

Hello all!! Im new to the site and am planning on buying a ff mk4. Im new to this stuf but have been around the fox body stuff for a while. Question is what independant rear are tou guys using on your roadsters? Are you guys using a 2000's corbra ind rear? Thanks for you help. Cant wait to start this new project!!

[riptide motorsport]

tbird IRS

[Rkloehn]

Will the 2000's ind. Cobra rear work? I know they bolt into fox bodys

[riptide motorsport]

I believe the answer is yes.

[Jacob McCrea]

Steven is correct. The caveat is that the later Cobra IRS center sections (i.e., everything but 1999, if my memory is correct) have a 31 spline Traction-lok unit, while the FFR half shafts are 28 spline. So, you would need to keep the housing, but switch out the 31 spline Traction-lok unit for a 28 spline unit.

It is great if you can find a center section from a T-Bird Super Coupe or a Cougar XR-7 with the Traction-lok differential already installed, but they are pretty hard to find in my experience. A Lincoln Mark 8 uses the correct differential housing, and it will be aluminum, but to date I have never seen one with a factory-installed Traction-lok diff, so you would probaly want to change it.

[J.D.]

According to my research Jacob has it right. The Cobra and Lincoln centers are aluminum while the Cougar and T-bird units were iron with an aluminum cover.

The problem with the Cobra IRS is the Spindles are different. FFR supplies correct length axles and control arms. Those control arms will only work with the T-bird, Cougar, and Lincoln spindles, which are all identical.

The Roadster uses a FFR designed IRS and will not accept the Cobra IRS assembly the way it can be bolted in place of a solid axle in another Mustang.

HTH

P.S.: I used a T-bird IRS and rebuilt it with a Truetrac Differential and 3.55 gears. I used 94 cobra rear brakes with an adapter to mount them to the spindles.

[Rkloehn]

awesome thanks alot for the responces

[Rkloehn]

So i take it guys with higher hp are using a solid rear with 31+ spline shafts? Will FF upgrade the 28 splines shafts for larger shaft spline for ind. Rears?

[Jim Schenck]

I think for the question you are asking about the Mustang IRS the answer is no. The 99-03 SVT IRS bolts into a Fox body as a unit but that unit will not bolt into the Roadster. What people are refering to above is the center section working with the FFR IRS, which will work if you have axles built for the 31 spline, however you will still need to source T-bird spindles and brakes. Factory Five doesn't have the 31 spline axles but others have had them made and maybe they can chime in as to where.

[riptide motorsport]

Now that is THE definitlive answer.