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Discussion Starter · #1 ·
I was yapping with an SVT mechanic about 03 Cobras and 03 Mach1's.

This tech told me that, when he test drove a Mach1, he was surprised by how closely it matched the 03 Cobra IRS. He said that it handled just as well and was just as comfortable too.

I have been trying to research the differences between the Mach1 axles and prior live axle Mustangs and can't find much info...other than "upgraded rear".

If the Mach1 rear is technically advanced then it may be a good candidate for a swap into an 03 Cobra. It's a solid unit so that would take care of the half-shaft issues.

Any information on the subject would be appreciated.
 

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Rich,

I am currently researching this also. I have a complete 02 GT rearend and plan on doing that as a build up. ( Moser, Locker, etc...) . I wondered too ?? about the 03 Mach 1 setup with the brakes already larger and the upgraded rear. I have a friend with a 02 Saleen 281E and it handles just as well as my IRS equiped cobra. Done right it would be a hard combo to beat.

Jon
 

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Night Trains Daddy
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I just did the swap

I have

99+ 8.8
Ford 31 Spline Trak Lok w/extra clutches
Superior 31 Spline Axles
X2C motorsports uppers and lowers
X2C motorsports rear drag coilover kit
I put on GT rotors, it would be easy to use the Cobra rotors you just need a bracket

You have to use the input off the IRS for out drive shaft to fit. Other than that it is a direct no hassle swap.

It is NOT as smooth over rough surface as the IRS but is not harsh at all either. I have no complaints and love being able to makes passes somewhat worry free.

As for the Mach 1 Rear the only difference could be the springs and shocks used. Maybe some different control arms or something...other than that there not much that could be different.
 

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Night Trains Daddy
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BTW, I sold my IRS for $1600 and that covered the price of the swap.
 

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With all due respect to the people that have done the swap, you take away from the Cobra's exclusivity when you do this. You take a factory car that you can throw around turns, or beat the hell out of in a straight line, and make it into more of a "one sided" car. I like the fact that my ass-end doesn't fly sideways when I go over a bump while making a turn. Hey, that's just my opinion. And Rich, weren't ya kicking around the idea of autocrossing at one point? Say bye-bye to that idea if you swap!!!! Especially with 617 to the wheels!
 

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Night Trains Daddy
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No cutting...just bolt right in.

SolidSnake - If I could have ordered the car from Ford with a solid axle I would have. I couldn't so I did it myself. I do see where your coming from, but I bought this car to race and racing is much more enjoyable for me when I'm not worried about snappin a half shaft everytime I launch
 

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I hear ya man, that should be an option. No doubt about it.
 

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SolidSnake said:
With all due respect to the people that have done the swap, you take away from the Cobra's exclusivity when you do this. You take a factory car that you can throw around turns, or beat the hell out of in a straight line, and make it into more of a "one sided" car. I like the fact that my ass-end doesn't fly sideways when I go over a bump while making a turn. Hey, that's just my opinion. And Rich, weren't ya kicking around the idea of autocrossing at one point? Say bye-bye to that idea if you swap!!!! Especially with 617 to the wheels!
OK, let's use that kind of reasoning for something else. The 03 Cobra came w/ an Eaton blower. It can kick ass as it is. If you swap on a KB, is that taking away from the Cobra's exclusivity? I don't hear anyone whining about that. Why? Because it makes the car better. For MANY people the live axle makes the car better for what they do with it. So whats the big deal about swapping to a live axle. It's better for drag racing and autocrossing. Period.

A torque-arm/panhard bar setup on a live axle will run circles around the factory IRS. Look at the American Iron series. How many guys run the IRS on their Mustang? Like one or two. And one of those guys I know for sure has plans to swap back to a live axle w/ a 3-link setup.

Darren
 

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Night Trains Daddy
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Actually I sold my IRS to a American Iron guy :)
 

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stlblack03- Did you do the swap your self or have a shop do it? How much would they charge do to the swap? If I had a shop do the install and bought a whole live axle set up will I still come out even?
 

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Discussion Starter · #14 ·
Here's a quote from one website's review on the Mach1 axle:

"Four-bar link with coil springs on lower arm, Unique horizontal axle damper and stabilizer bar "

I have actually seen this description on many sites. I know nothing about this yet but perhaps it's the "unique horizontal axle damper" that makes the car drive and handle like an 03. Maybe it's better for the bumps on the road?

We need some technical info. Would it be a direct bolt-on? Any issues? This REALLY has my interest.

Solidsnake: You forgot to list your chip and tune in your signature. And get to the track and break your cherry!!
 

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'99 & '01 Cobra owners have been doing this swap for years.
Usually, they just find a GT owner who wants improved handling & comfort, and they simply swap assemblies & all the associated parts.

As far as the '03 Mach 1 having ride & handling equal to the IRS - IT'S JUST NOT TRUE, no matter what you have been told.
The Mach 1 rear suspension is soft & comfortable, but it's no IRS by any stretch of the imagination. You CAN modify the 8.8 solid to handle like the IRS - or even better - but you'll spend several thousand dollars ++ on top of the 8.8 swap to buy a panhard bar, torque arm, upper & lower control arms, etc, etc.

"Unique horizontal axle dampers" is probably just a fancy name for quad shocks with a different valving.

I'm not saying the swap isn't worth it - if drag racing is your primary concern, then a live-axle swap is a no-brainer and well-worth the effort in reduced 60' times & lower ET's with less chance of parts breakage (live-axle cars still break parts, just less frequently). The '99 & '01 guys figured this all out years ago BTW
(all the '99 & '01 guys in the 11's with stock 4V motors are running live axles), so you're not re-inventing the wheel here - it's been done successfully MANY times before.... ;)
 

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Hey Rich, how have you been? I swapped out the IRS in my Cobra as one of my first mods. It is not that difficult, but it does take a little time if you are doing it by yourself. I bought a complete 8.8 set up from disc to disc and then rebuilt and replaced everything to my liking. I had the axle tubes welded and then filled the rear with a Detroit "C" locker, 31 spline Superior axles, a steel bearing cap, 3.90's and a T/A stud girdle. I used UPR double adjustable uppers, HPM Megabite Jr's, Hal QA1 12 way adjustable shocks and an Eibach drag launch rear spring set with an air bag. I retained the stock 03 Cobra brakes by swapping out a couple of brackets. Then I had all of the components powdercoated black so they would look nice. This set up does not handle anything like the IRS, and is downright unfriendly on the street at times, but it will sure take a beating. I wouldn't dream of going back to the IRS unless I quit drag racing, but I've got it in the garage under a tarp just in case. The above set up has yielded a best 60ft. time of 1.57 so far. I think 1.40's are possible if I can do my part. Just a rough estimate on cost, I would say right at $3000. If you need any help or have any other questions, feel free to ask. Take care, Bob.
 

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I second what Angus posted. The Mach 1 may be a nice ride, but it won't take a bump mid corner like an IRS. It will get out of control. Swapping in the stock Ford parts is not really the greatest setup. But it works. And is pretty damn good for drag racing. But you could go the whole MM or Griggs route and end up with a car that feels like it's on rails.

Just take a MACH for a test drive. Then you'll see first hand.
 

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Just get a 99+ GT live axle. To me the IRS does not drive that much better anyway. If you want a cushiony ride, buy a Cadillac :D A stock solid axle 8.8 should be built as well. I plan on going with a 99GT rear, with a locker and 31 spline axles, and complete UPR suspension kit.
 

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I have an 03 with IRS, and am hearing a poping noise when I turn right, into a slight incline, like most parking lot entrances. It does not seem to do it when pulling out or going down a slight incline. Since many of you seem familiar with IRS, perhaps you may have run into this problem or might know what is wrong.
 
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