You've probably seen the television commercials that feature these incredibly overweight people who have lost 150 or more pounds. They all say the same thing: "This has changed my life." When it comes to high-performance street cars, there's nothing more lifestyle changing than a serious suspension upgrade that converts a strictly straight-ahead machine to one that can now negotiate corners with impressive control. Let this be said: Turning corners is fun.
Last month we introduced you to Shannon Hudson's lime-green '69 Plymouth Valiant when we outlined regearing his 83/4-inch rearend from 4.10:1 to 3.55:1. At the same time, John Hotchkis of Hotchkis Performance was looking for a car to test his new line of Mopar suspension components on for the popular A-Bodies, such as the Dodge Dart, Dodge Swinger, and Plymouth Valiant models. Hudson's bright-green cruiser offered the perfect opportunity, and we soon found the green beast slogging its way through a Hotchkis baseline test at Willow Springs' Streets of Willow track. With a drag race package that included skinny fronts and drag radial rears, the Valiant was, as we expected, underwhelming on the skidpad and 600-foot slalom course.
Next, it was off to the Hotchkis Performance shop where chief engineer Aaron Ogawa designed the 69 Plymouth Valiant upgrades to minimize the compliance as well as a little body roll on the way to a superior-handling suspension. The conversion would also include swapping to a set of front and rear Right Stuff disc brakes, a quicker Flaming River manual steering box, while riding on a set of General UHP tires and a beautiful set of Curtis Speed wheels. We won't go into the boring details of how to swap all these parts since the installation is virtually a bolt-on with the exception of the weld-on sway bar brackets. We'll hit the important bits and concentrate more on how all these parts integrate to transform the lime-green Mopar into an excellent-handling road car that Hudson will now use to attack those twisty mountain roads just north of his shop.
69 Plymouth Valiant - Front-End Chemistry
Mopars are somewhat unique in the front suspension area with their use of torsion bars, which are really nothing more than straightened coil springs. The torsion bar is mounted into the narrow lower control arm that is triangulated with a strut bar, much like an early Mustang front suspension. Add in an upper control arm to locate the top of the spindle and you have a basic A-Body front suspension. Hotchkis' goal was to improve on this basic system by removing as much rubber as possible while adding additional caster and camber to allow planting the front tire to optimize traction in the corners.
69 Plymouth Valiant - Bringing Up the Rear
If the front suspension was easy to install, the rear is even easier. The Hotchkis springs are significantly different from the previous Mopar Performance Super Stock drag race leaves that had one additional leaf on the right side. All Mopar leaf springs are asymmetrical, meaning the portion of the spring from the housing to the front spring eye is shorter than the rear. This automatically strengthens the front spring section to virtually eliminate wheelhop. The Hotchkis springs are the same rate side to side to make handling more predictable but also reorient the way the springs are placed on each leaf. The main leaf in stock springs is the one that connects to the pivot on both ends, but the Hotchkis springs assign that job to the second leaf, using the top leaf as a reinforcement to minimize main leaf wrapup. The Hotchkis spring is rated at 130 pounds per inch (lb/in), while the Mopar drag springs use two different rates, with the passenger side measuring an average of 170 lb/in and the driver side at a slightly lower 160 lb/in. Hotchkis also includes a new four-bolt front spring eye hanger that raises the front spring eye location to reduce roll steer.
The first thing technician Cody Bedotha did was release the load on the torsion bar by rem
The Hotchkis strut rod uses a spherical bearing in place of the large rubber bushings. Thi
To mount the upper control arms, Bedotha had to trim a small portion from the original upp
With the new Hotchkis leaf springs in place, Bedotha dropped the car on its tires to sit a
Bedotha then moved to the front to mount the 1 1/2-inch-diameter front sway bar. The Hotch
Here is the final system in place with new upper Hotchkis control arms, a strut rod, steer