Before we get into showing you how we upgraded the suspension on our A-body, here's a little background into why we did it. We covered the build and installation of the 427-inch stroker small block into our '68 Valiant in the June 2011 issue. With the new 427 under the hood, the car was so fast that some upgrades to the chassis were necessary. It literally became a safety issue. Let's face it, running 150 mph in a '68 Valiant has a way of forcing you to focus your attention onto items such as the suspension, brakes and oiling system!
While these A-Body cars are a little lighter than either the B or E-Body cars, they are still heavy compared to some of the other cars that show up to race on open track days. The power of the 427 inch engine does help to equal things out a bit, but weight reduction has always been one of the cheapest ways to go faster. Not only will a lighter car accelerate faster, but it will corner harder and stop faster than a heavy car. Knowing this, we decided to take a serious look at each component on the car to see if there was any opportunity to shave a few pounds. Because these cars are naturally nose-heavy, we focused most of our weight reduction efforts at the front of the car. We were able to save big chunks of weight with the aluminum cylinder heads and the aluminum transmission case. We found smaller weight savings by switching to Schumacher motor mounts, cutting some bracing out of the hood, changing anti-sway bars, swapping headers, and installing new brakes.
1. These three anti-sway...
1. These three anti-sway bars all fit the 1973 style K-frame in our Valiant. The factory bar at the top doesn’t have enough roll resistance for the cornering speeds that this car is capable of. The black bar in the middle worked fine but it weighs 14 pounds. The tubular Hellwig bar at the bottom of the picture only weighs eight pounds. Six pounds might not sound like a substantial weight savings, but when added with all of the other weight shaving, it adds up.
The suspension under the Valiant is stock configuration, although very few original parts are still in place. The original K-frame and suspension was replaced years ago with parts from a '73 A-Body car. The later model anti-sway bar was an excellent design, but the factory bar is too soft for track use, so it was replaced with a 11⁄8-inch diameter bar. This larger bar worked fine but was very heavy, so we went looking for a replacement.
With a little bit of research we found out that Hellwig had a selection of lightweight Mopar anti-sway bars fabricated from high strength steel tubing. By increasing the outer diameter of the bar, a tubular anti-sway bar is both stiffer and lighter than a solid bar. Hellwig offers 1-1⁄4-inch bars as well as 1-1⁄8-inch tubular style anti-sway bars. We decided to go with the 1-1⁄8 version even though that meant that our front roll stiffness would decrease slightly. We felt that a slightly softer front bar would work fine once we had finished with our other weight reductions up front.
2. The Hellwig kit included...
2. The Hellwig kit included all of the required mounting hardware, but we decided to make our own extra heavy-duty end link spacers from one-inch diameter aluminum. These large diameter spacers reduce compliance in the bushings and slightly increase the roll resistance.
An adjustable rear anti-sway bar was also fitted to the car to provide additional rear roll stiffness. This particular rear bar was custom built to work with the low ride height, but vendors such as Firm Feel offer similar rear anti-sway bars. This bar was mounted on the frame in an effort to reduce un-sprung weight. The end link location on this bar is adjustable, which allows us to increase the rear roll stiffness for autocross events.
3. The rear anti-sway bar...
3. The rear anti-sway bar on this car has multiple mounting locations for the end links. The closer the links are to the end of the bar, the lower the roll resistance. As you can see, the rear bar is set up initially in the softest position. The roll resistance can be increased by moving the end link forward.
4. The front suspension includes...
4. The front suspension includes a pair of Firm Feel upper control arms and a set of custom Bilstein shock absorbers. The guys at Firm Feel were an excellent source of information when it came time to select shock absorbers.
5. C-Body tie rod ends were...
5. C-Body tie rod ends were installed along with large diameter billet adjusters from Firm Feel. These parts add a little weight to the suspension, but that seems like a fair price to pay for the extra rigidity.