It can't be helped that we see all muscle cars through a performance mindset. That's the original marketing we remember that created our first impressions. The bigger the engine, the more carbs, the bolder the graphics—the more we dreamed about, desired, and coveted the high-performance versions. The factory used performance to sell and we are still reaping the benefits of that strategy all these decades later.

But we also bought into a fantasy of sorts, and that is that these cars were designed with nothing but performance in mind. Truth is, Chrysler didn't make its real profits off of fanatical gearheads that were willing to spend a month's wages chasing another tenth of a second at the track. They earned their keep selling daily drivers to the masses who mostly only cared about the purchase price and the overall economy of getting around town.

This meant that design and production costs mattered and that the cars were really built to satisfy the average consumer. That's not to say that the designs were bad—hardly. It's just that they weren't—and really couldn't be—build strictly for performance use.

Fortunately, we have no such limitations today. Innovative companies such as Reilly Motorsports can engineer solutions that simply weren't doable more than four decades ago.

One such product is Reilly Motorsports' Street-Lynx triangulated four-link rear suspension system. As you know, '70-'74 E-Bodies are leaf-spring cars. Rear leaf springs are fine for general driving but they are not so hot for a true performance application. Leaf springs are heavy, somewhat slow to react to road conditions, and don't control axle wrap in high power situations. They are also non-adjustable.

The Street-Lynx kit solves a number of problems by separating what supports the car from what locates the axle. This reduces unsprung weight, makes for a better ride, and makes the ride height easily adjustable. Axle wrap is eliminated and the optimum pinion angle can set with confidence. An added bonus is some additional inside tire clearance.

Using a four-link suspension allowed RMS to get the geometry right without ruining the ride quality. This means that your car will be able to handle high levels of power and still provide a smooth ride. It can also be adjusted for better track performance and then quickly be returned to the normal street configuration at the end of the day. The kit also ships with Viking coilover double-adjustable shocks as standard.

Installing the kit has to be about as easy as it can get. A crossbar needs to be welded between the frame rails, and some mounting tabs will have to be welded to the axle housing to locate the upper links, but no other modifications to the car are required. There could be some minor brake line modifications but the kit allows the use of the stock fuel tank and even off-the-shelf tailpipe kits if an 8.75-inch rearend is planned. (Dana 60 or Ford 9-inch applications will require custom exhaust exits either in front of the axle or below the axle.)

Muscle Car Restorations did this install while the car was in the sheetmetal repair part of the resto so it was still just a shell with nothing in the way. If you are going to install this kit in your driver, you'll want to remove the fuel tank and fuel lines and the brake lines with the axle. It's imperative that you remove any possibility of any fuel being present when you are welding to the frame rails. Of course any tailpipes will need to be removed as well.

The manual that comes with the kit is detailed, well illustrated, and easy to follow. It also includes complete info on how to fine tune the system for your car.

Read More!

Want to know more about Reilly Motorsportss AlterKtion front suspension and how to install it into a Mopar A-Body? Click here:

Want to see how the Reilly Motorsports Street-Lynx rear four-link suspension is installed in a Mopar A-Body? Click here:

See all 22 photos The Reilly Motorsports Street-Lynx system (PN RMS553, $1,995) is a complete kit that converts your leaf spring rear into an adjustable four-link without any major fabrication. Only an upper crossbar needs to be welded in between the existing frame rails.

See all 22 photos Save any paint, powder coating, or general rebuild processes until after the install is complete. A pair of upper link tabs will need to be welded to the top of each axle tube so a thorough cleaning to bare metal will be necessary on each side of the housing.

See all 22 photos In some cases, the axle vent/brake tee may interfere with the driver-side upper link tabs. MCR routinely relocates it to the top of the housing and welds up the original hole.

See all 22 photos The upper crossbar is positioned between the frame rails and is positively located by lining up a tab on each side with the forward bump-stop mounting hole. Use one of the bump stop screws to hold it in place. Depending on the car, the crossbar fit could be pounded in tight, or be so loose as to require welding an extra plate to the rail first. A precise fit is not necessary.

See all 22 photos What is important is that your weld goes around the entire plate and also in each of the 1-inch holes for maximum strength.

See all 22 photos As you can imagine, the RMS crossbar not only provides an attachment point for the upper links, it also greatly strengthens the back half of the car.

See all 22 photos The axle plates mount to the existing spring perches using RMS supplied u-bolts. The shock mounts will face forward and to the inside of the lower link mounting points.

See all 22 photos There are four attachment holes for the aluminum shock mount. Using the center two is the most common.

See all 22 photos For 1970-'74 E-Bodies, the lower links should be adjusted to 22.5 inches center to center.

See all 22 photos

See all 22 photos The lower links are first bolted into the supplied hanger which is then bolted into the factory leaf spring torque. The two images are of the same thing, but from the front and rear. Be sure to mount the link with the grease fitting pointing down.

See all 22 photos The upper links are less precise at this point. Simply be sure they are the same length with a quarter inch of thread showing.

See all 22 photos With a suitable jack or stands, raise the axle under the car and attach the lower links to the upper hole on the axle bracket. Adjust the height of the axle until the lower bars are close to level. Note that the upper bars and mounting tabs are in place but the mounting tabs are not yet welded. The distance between the upper and lower shock mounts should be 13.5 to 14 inches, which is the approximate center of the shock travel.

See all 22 photos Next, center the axle in the car by holding a straightedge on the axle flange and measuring to the frame rail on each side. Shift the axle on the jack as needed.

See all 22 photos Twist the axle to set the pinion angle to 1 degree up. Since this is not a leaf spring system, the axle will not wrap. No further angle changes should be needed and it is not necessary to check the engine/trans angle.

See all 22 photos With the axle in place, position the upper link mounting tabs on the housing. Longer and shorter tabs are supplied in the kit to compensate for the angle of the housing. Some grinding might be necessary for a clean fit and to get the front and rear bushings to line up. Be sure that the tabs are parallel to each other so they don't bind the rod end. Just tack each one in place and finish the welds after the axle is down again.

See all 22 photos The last step is to install the shocks and follow the kit's instructions for setting the ride height, and compression and rebound stiffness. Once the car is on its wheels, it's important to recheck that the axle is still centered. Minor centering adjustments can be made with the upper links. Also recheck that the axle is square with the car (using lower link adjustments) and note that any tweaking can also affect the pinion angle.

See all 22 photos Here's another view from the rear.