Independent Rear Suspension?

2BADSTANGS

Member
Jun 19, 2008
385
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Colorado
I have a 99' cobra with the IRS and gave a ride to my buddy with a 67' stang'. He asked if it were possible (without spending millions) to adapt an IRS setup to his stang? I dont know too much about the pre-fox stangs. Does anyone know if there is an IRS kit for the older stangs? Does anyone have first hand knowledge about the difficulty/ probability of adapting one? Thanks!
 
I've done both the Heidt's kit and adapted a 2003 Cobra IRS. The Heidt's kit requires lots of fabrication. It's a universal kit not designed specifically for the Mustang. It is available in a variety of widths so it can fit all cars.

The Cobra IRS is too wide for 65/66 cars without major flares. With the DVS kit it's basically a bolt in. Cobra IRS assemblies show up on Ebay all the time. I modified the cradle myself to allow me to lower the car further. Since I didn't buy the DVS kit it required lots of fabrication also.

Daze did a nice job with the Jag IRS but one again, much fabrication.

There are some complete bolt in kits available but they are around $9k

They're probably all more work and money than they are worth. Yes, they ride better and potentially can handle better but I doubt I'll do another one.
 
there are also these guys as well.

http://mustangirs.com/

there is another company called Control Freaks that have an IRS kit as well but it's like $8,000 and the welds on the kit i've seen installed (the one on their site) look like a 12 year old metal shop student did them. i'd stay far away from that kit. another thing about that kit i didn't like was that you have to cut out a section of frame rail and make C-notch, this in a sheetmetal frame rail and you have to cut out about 3/4 of the rail for this notch.....not good.

if it were me i'd do the DVS kit or the Mustang IRS kit.
 
I've been following the mustangirs progress for awhile but didn't realize they had a complete bolt in kit ready. They only charge $500 for installation so it must be pretty easy to install. It looks like a good set up but in the video you can see the lower A arm isn't parallel to the ground at rest so there will more than ideal camber change. Perhaps that can be adjusted by lowering the car. It might have been a factory design but it was still confined to fit into an existing chasis (much like the Cobra IRS was packaged to fit the Fox chassis) so compromises had to be made.

Interesting that they've adapted it to the new Mustangs too. If it wasn't $8k I might be tempted to put one in my 06.
 
It looks like a good set up but in the video you can see the lower A arm isn't parallel to the ground at rest so there will more than ideal camber change.

The half shafts appear to at be nearly the same angle, so the camber gain may not be so severe under normal driving. With the half shafts being shorter it probably gains more at the top.
 
Honestly the Fox IRS swap is a bolt in. Since the frame is the same from 79-04, there is very little difference between any of them other than the sn95s are a tad longer. The hardest part of the whole swap is redoing the brake lines and the balancing act of having a 200 lbs irs on your jack while trying to bolt it in a ft in the air.
Kevin