5/27/10: Replaced the rear wheel bearings on the IRS as they are a weak point in the design and one was on its way out. They are done and back in the car again now after cleaning them up and pressing in new bearings. Also mocked up the front sway bar and fabricated most of the parts needed for the rear spring perches. Need to grab some more pictures and post them.

3/31/10: Moving right along.. been a busy week. Our goal was to have the car ready to go on the ground by the end of March. We were working right up until 12:00 and baraly finished most everthing. Just need to finish up the rotisserie and it can go back on the ground for the first time.
Drilled out the frame for crush tubes and welded those into the frame so the brackets can be safely bolted to the frame structure. Once those were done, it was time to weld the tubes at all 4 corners of the assembly. We pulled the entire IRS out and finished all of the welds up. It kinda looks like the tubes came that way from the factory

3/24/10: The push is now on to get the rear on the ground. We cut the rear mount to size and welded the tube to it. Just need to drill holes through bracket and frame rails, weld in crush sleeves and weld the tube to the IRS cradle. The front mounts are also done and just need to be welded to the IRS cradle. After that it will bolt right up to the frame in the rear. That leaves the shock mounts and springs mounts which are also nearing completion. Looks like we will be on the ground soon. Just need the rotisserie done so we can pick it up of the chassis jig and put it back down on the ground.

3/14/10: Time to catch up on the rear suspension. Finally decided how to do the rear mounts on the IRS. We used one of the 2.5"x1/8" tubes we have made up for the front mounts, cut one in half and will use the 2 pieces to make up both rear mounts. We lucked out and it looks as though the rear tubes use the same 5" radius as our bends do. Big thing is the rear mount will still clear the 315's with stock wheel lips. Just need to go grab some more steel to make up the actual brackets that bolt to the frame as we used a scrap piece for now that was a bit too small. Next we need to make up pockets in the frame for the shocks and clearance for the upper control arms. We'll be on the ground in no time.

3/08/10: Time to catch up on the rear suspension. Finally decided how to do the rear mounts on the IRS. We used one of the 2.5"x1/8" tubes we have made up for the front mounts, cut one in half and will use the 2 pieces to make up both rear mounts. We lucked out and it looks as though the rear tubes use the same 5" radius as our bends do. Big thing is the rear mount will still clear the 315's with stock wheel lips. Just need to go grab some more steel to make up the actual brackets that bolt to the frame as we used a scrap piece for now that was a bit too small. Next we need to make up pockets in the frame for the shocks and clearance for the upper control arms. We'll be on the ground in no time.

1/27/10: Since the front suspension is finishing up, time to move back to the rear once again. Had a lot of time to think about this one now, so time to put it in action. Biggest issue with designing anything in the rear is the tire clearance. Fitting the 315's back there requires lots of room. Couple of constraints here - the outer fender lip since the tire will sit within it, the springs and the shocks. We went back and forth on coil over shocks, but in the end they are expensive and take up precious tire clearance. They also do not provide the most desirable load path as the shock mounting holes are outboard of the frame rail (many of the aftermarket kits out there use single shear mounts on the outside of the frame rail which we are not big fans of). The shocks even without the coil-overs will require notching the frame, although very minimally. The result here.. the springs and shocks will mount in separate locations like the stock Mustang.

In the end, this is how we decided to mount the spring. We are using the stock spring pocket on the lower control arm, but using a much smaller spring. We started with 2 u-bends as you can see, and turned them into a doughnut. This way we maximize surface area to distribute the load. Just need to add a flat plate in the middle and a small wedge to angle the spring as required. Then we simply add a mount to the frame rail. Notice we are also adding an adjustable sleeve for fine tuning the ride height. Since we are running fairly stiff springs all around, we will be using helper springs (very low stiffness) to keep the springs in place when the suspension goes into full rebound.

12/16/09 - Found a set of nearly new rear adjustable Konis specifically made for the IRS suspension. Just need to make some custom upper mounts now.

2/26/09 - Fabrication is nearly complete on the front IRS cradle suspension mounts. As you can see, they tie into the existing leaf spring mount. We cut a sction of 2" steel and notched out the 2.5" main tube - worked perfect. Another days worth of work and they will be ready to weld in. Getting closer to getting the car down on the ground. We decided to rigid mount these instead of using rubber bushings like the factory ones.

2/16/09 - IRS parts show up. IRS tubes showed up today which will allow us to complete the rear suspension install. These are 2.5" x 1/8 wall tubes we had custom CNC mandrel bent for this application. They came out great as you can see.

8/10/08 - IRS Trial Fit on Chassis Jig

We are finally at a point where the chassis jig is becoming very useful.  Here are some images of the IRS being put on the cradle, and then loaded up on the jig.  This sure makes life 100x easier when trying to position things.  The IRS mounts will have to be cut and re-welded to allow the suspension to go into the position that we require.  That work with pics is soon to come.

4/15/07 - IRS Trial Fit

We pulled the rear axle out today to begin the fit-up of our 2004 Cobra IRS into the Texas Torino.  Removing the axle assembly proved to take much longer than planned, especially when we had to get the torches out.  As you can see, the unit fits the Torino pretty well.

We are still deciding on how to tie the sub frame into the Torino's body.  The direction we are likely going to take is to extend the front mount points to tie into the stock spring perch location for a cleaner look.  The trunk floor will definitely need to be notched to clear the upper control arm which will allow us to push the IRS up for better ground clearance.  In order to run wider tires, we will need to move the rear points inward, which will also make for better load transfer into the frame rails.

With the rear suspension, leaf springs are standard fare from the factory.  The optional traction bars are definitely a 60's bonus item.  8" rear will be history in favor of an 8.8" with the Cobra IRS.