Rear Suspension Upgrade For Your Classic Mustang

Our Magna suspension items from Mustangs Plus will soon be at home with the rest of our Magna parts on our '66 Project Mustang. We will hold off on installing the rear sway bar until after the driveline has been installed, but we are showing it here.

In our July 2000 issue, we completed the conversion from six-cylinder front suspension and brakes to the safer, correct V-8 counterparts for our '66 hardtop project. The installation went smoothly, so we thought we would tempt fate this month by finishing up our V-8 suspension and brakes conversion at the other end of our hardtop. While we are opting to replace the complete axle housing and all suspension in one fell swoop, you can use this article as a guide for any one of a number of smaller projects, such as shock replacements or shackle bushing replacement, or simply use the detailing part of it to bring your V-8 suspension up to snuff.

After our Currie Enterprises Super Eight-Inch rear axle assembly arrived, we promptly detailed it out with some fine concours detailing parts from National Parts Depot, including stainless brake lines, an axle vent hose kit, and more (see the sidebar To the Nines). We then gathered up the remaining Magna suspension items from Mustangs Plus that have been itching to join their sister parts on our hardtop, and we put everything together for a complete V-8 suspension and braking upgrade for our hardtop. With the rear suspension and brakes completed, our next stop will be paint prep and applying several coats of Anniversary Gold to our hardtop's new skin. Follow our lead as we rip out the old six-cylinder axle, the brakes, and the suspension in favor of their new V-8 capable counterparts.

1 With the rear of the car supported by jackstands, and the axle itself supported by a floor jack, the rear shackles can be unbolted. Slide the leaf spring off the shackles, and pull the shackles (and bushings) free of the rear framerails.	2 Instead of fighting with rusty old U-bolts, we decided to remove the axle and rear suspension as an assembly. After unbolting the top shock mount, we lowered the rearend, took wrench to nut (left), and freed the driver-side leaf spring eyebolt (right).	3 Instead of fighting with rusty old U-bolts, we decided to remove the axle and rear suspension as an assembly. After unbolting the top shock mount, we lowered the rearend, took wrench to nut (left), and freed the driver-side leaf spring eyebolt (right).
4 The passenger-side eyebolt didn't fare as well. The bolt had seized to the inner sleeve of the front eye bushing. This is quite common and takes cutting of the bolt to free the spring from the body. A SawZall works well for this.	5 With the front spring eyes free of the rear framerails, it was simply a matter of rolling the rear axle and suspension assembly out from under the body. Of course, the driveshaft and the brake lines were already removed, so make sure you take care of those as well.	6 With the rear suspension and axle removed, there was plenty of room for cleaning, painting, undercoating, rust repairs, and more. So take a good look before you start bolting on your new parts. We began by installing our new Magna 411/42 leaf springs with new front eyebolt hardware.
7 Mustangs Plus offers several different suspension options to match your driving and handling tastes. Aside from our mideye springs (to lower the car an inch), you can choose from stock shackles, urethane leaf/shackle bushing kits, and these heavy-duty design shackles.	8 Next, with borrowed five-lug wheels attached, the new Currie rearend was rolled in place over the springs.	9 We opted for the stealth look by using stock shackles with urethane bushings. The urethane bushings come with waterproof grease to fend off squeaks. Liberally apply the grease, and then install the bushings into the rear eye of the springs.
10 Since we didn't want to get jack marks on our newly detailed rear axle, we simply lifted the leaf springs up, aligning the spring center bolt with the axle perch, and then slid the shackles into place.	11 It took some effort (eat your Wheaties), but this kept us from scratching our rearend (hold the jokes).	12 The shackles were only "snugged" down here since the '66 wasn't on its full weight. When the car is completed and aligned, we will fully tighten all the suspension hardware. Don't forget to tighten yours.
13 Since Currie's Super Eight is based on a '67 housing, we required the '67-styled spring plates and larger U-bolts. The U-bolts we already had and the new spring plates came from National Parts Depot's detailing items. We started the mounting nuts by hand, and then evenly tightened them in an "X" pattern. Make sure the spring plates are correctly installed. Otherwise, the shocks will not seat correctly.	14 Our MagnaGas shocks are shown here dressed for the prom in correct black and with the white paint daub. We didn't go all the way and fill in the shock-body lettering, though. The MagnaGas shocks come with all new hardware and bushings, so there are no 36-year-old parts to clean up and reuse.	15 The axle vent hose kit includes the correct clamp with bolt and the frame grommet needed to complete the job, so we routed the hose to the frame grommet and secured the clamp to the original location. Lookin' good.