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Discussion Starter · #1 ·
While I'm waiting for delivery of my kit, I'm trying to put together all the additional parts I'm going to need. With the IRS, other than the T-bird 1989-97 parts, will the IRS parts,( the carrier, inner & outer CV joints, spindles, and disc brakes), from a 2003/04 Cobra Mustang work? If not, will the CV joints for the T-bird work with the Carrier & spindles from the Mustang? Again, if not, will the spindles and brakes from the Mustang work on the T-bird axles? Sorry for all the questions, but I have never seen anything mentioned on the newer Mustang, especially the Cobra, IRS parts.
Thanks in advance guys.
Rick
 

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The part of the CV that goes in the center section (AKA the pumpkin) is 28 spline on the Tbirds + MkVIIIs.

It's 31 spline on (at least some, maybe all) Cobra centers.


I *think* the Cobra hubs are the same as Tbird (except with the preferred 4.5" bolt pattern + 1/2-20 studs on the Cobra vs metric on the Tbird).

I *think* the Cobra spindles are the same as Tbird.

I *think* the Cobra brakes will work - I haven't worked with them at all.

HTH,

Mike

P.S. Tbird stuff is plentiful + cheap at junkyards, Cobra stuff, not so much...
 

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the t bird spindals are different
they have 4.25 inch centers
the cobras have 4.5 inch centers
the t bird spindals need to be redrilled
i had mine done by stu. IRS Machining Services
he did a great job, cleaned everything pressed my new bearings in drilled the holes.
mine came with new half shafts (28 spline)
as for brakes i read the t bird brakes are good
if you use the then you need the rooters drilled also
or you can get the adaptors and use the cobra rear brakes
 

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Discussion Starter · #5 ·
Thanks for the replies guys. So if I understand, the spindles will work, but not the hubs, (31 spline versus 28 spline), and I understand that the T-bird brakes are OK, but just single piston. I have access to Cobra rear two piston brakes. Will these work with T-Bird hubs?
Thanks again,
Rick
 

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EZ$: I recommend you take a look at the advertisers link above above. A number of vendors offer parts for the IRS. Beeeze, Forte's parts as well as others, have a lot of parts relating to the IRS. You also might find this helpfull. Go to google (link below) and enter the following: site:ffrcars.com IRS hubs or anything else you want info about, like IRS brake upgrades, IRS sway bars, IRS solid mounts, etc. Lots of stuff out there for the IRS you just need to look around. I found this very usefull when I had a question.
Keep in touch, you are hanging out in the right place.
HTH
CB
 

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Discussion Starter · #7 ·
Cone Basher,
Thanks for the info. I hadn't figured out the search process relating to finding specific items. Right now, my intent is to check the salvage yards first for the T-Bird stuff, and If I can't find what I need then I'll resort to buying from one of the vendors. (Cost is really the issue right now. Pay no attention to my forum name:)) It's just a bit confusing. Trying to determine what works together, when the FFR manual doesn't spend much time on the IRS, is tough.
Rick
 

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EZ$: When I built my kit I use a rear assembly from a T-Birb SC ($600) which has a cast 8.8 center section locker. The outer hubs were fine but I did have to have the hubs pressed apart and redrilled for the bolt spacing to fit the front wheels and swaped the axles for the FFR ones that came with my kit, messy job but it can be done Breeze sells the ready to go if you do not want to tackle it. I also found a set of SN 95 spindles , 13 inch brakes and rotors from a 94 Mustang Cobra on e-bay for $200 for the front. If you are looking at salvage yard parts be sure you get an 8.8 locker, other Ford cars have the 8.8 and some are aluminum but the cast center section is the one you want for high hp.
Keep in touch, all here are willing to share their build experience:
CB
 

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but not the hubs, (31 spline versus 28 spline),<snip> and I understand that the T-bird brakes are OK, but just single piston. I have access to Cobra rear two piston brakes. Will these work with T-Bird hubs?

The spindles (aluminum knuckles) are good (any).

The hubs (where the wheel studs are) - those are good too. The Cobra hubs are preferable to the Tbird hubs because the Tbird hubs have to be redrilled for 4.5" bolt pattern. The Cobra hubs are the same splines as the Tbird.

The center section of the Cobra IRS and the inner part of the Cobra CV assemblies is *probably** going to be 31 spline. The CV assemblies FFR is going to supply are going to be 28 spline (but you might could get FFR to send 31 spline stuff, you'd have to ask them about that).

I've got nothing on the brakes.

HTH,

Mike
 

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The Spindles on the Mustangs are NOT going to work.

Get the Bird or MK 8 parts and get Cobra hubs. I think the center section will work but it will be a ton more money.

Ping Sergio he used more of the cobra IRS than anyone. HTH, Richard.
 

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My kit came with complete axles, CVs already installed. If you get full axles they will be 28 spline. These will only fit the T-bird (cast iron) or Mark VIII (aluminum) center carriers. You can find locking T-bird units but all the Mark VIII units are open. If you used a Cobra center section you would also need the axles and have them cut to fit. You need the T-bird or Mark VIII spindles, Cobra spindles mount differently. As far as the hubs, use the ones for the brakes you plan to use. They will fit the rotors best. (the center ring on the T-bird/Mark VIII hubs is smaller)

Steve
 

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You need the T-bird or Mark VIII spindles, Cobra spindles mount differently.
Just to be clear - I definately defer to the last two posts (Steve + Richard) regarding he Cobra spindles (aluminum knuckles).

I've never laid hands on one (Cobra spindle), but somewhere I got the (mistaken) impression that they were the same. They look similar in illustrated parts drawings.

Mike
 

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Discussion Starter · #13 ·
Thanks guys. I'm going to try to find the T bird rear, and see if the cobra hubs will fit, so that I can use piston calipers. On another item, can anyone explain why there seem to be two threads within this topic? A couple of the responses don't align with the remainder of the thread.
Thanks again,
Rick
 

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T Bird SC

If you can get a rear clip from a T-Bird SC all all you have to worry about is the conversion from 4 to 5 lugs. Be careful about getting a rear clip out of one of the smaller engined cars. This will produce headaches.

I got an entire rear clip for $350.00. It had a 3.08 pumpkin that worked out just fine for me.
 
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