1965 Oldsmobile Cutlass - Parking Lot Brawler - PHR Project Car

The upper coilover bracket is a two-piece design that sandwiches the framerail. Jarvis first placed the upper doubler plates on the top side of the chassis, then threaded a 3/8-inch bolt into them from the bottom side of the car using the outermost holes. In the two remaining holes, 3/8-inch capscrews were fed into the doubler plates and cinched down with Nylok nuts on top. All bolts were then torqued to 35 lb-ft.

The lower coilover conversion bracket mounts to the lower control arm bracket with three bolts. Using existing holes on each lower control arm bracket, Jarvis attached the coilover bracket with 1/2-inch bolts and Nylok nuts. Next, using the coilover bracket as a template, two 5/16-inch holes were drilled into each factory bracket. With the mounting holes drilled, the coilover brackets were torqued to 25 lb-ft on the 5/16-inch bolts and 80 lb-ft on the 1/2-inch bolts.

Before reinstalling the rearend, the control arms and coilovers were attached finger-tight to the chassis side of the car. Getting everything to line up properly to their attachment points on the rearend can take some muscle, so it's helpful to leave some free play in the bolts.

With the control arms and coilovers attached to both the chassis and rearend, Jarvis torqued the bolts down to spec. DSE recommends using high-strength Loctite on the upper shock bolts, and tightening both ends to 70 lb-ft. The control arms require 110 lb-ft. While a spring rate of 150 lb/in might seem soft, it's important to remember that the stock Cutlass had no rear sway bar at all, and the addition of the DSE bar will increase roll stiffness dramatically. Furthermore, the A-body features springs that are mounted directly to the rearend housing, which yields an effective wheel rate that's identical to the spring rate. In cars where the springs are mounted in the control arms, the resulting linkage ratios create a wheel rate that's often far softer than the actual spring rate.

Although the final ride height won't be dialed in until the front suspension is installed next month, Jarvis says it's important to set the baseline height as accurately as possible. He first threaded the coilover adjusting nut until he felt a slight amount of tension, then turned the nut three to four more rounds. Measuring between the base of the shock and the bottom of the adjusting nut with a caliper helps ensure that the left and right sides of the car are sitting evenly.

A-bodies use a triangulated four-link, which eliminates the need for a Panhard bar. Consequently, the upper control arms are angled outward, which means that varying their length moves the rearend from side to side. With the tires reattached and the car back on the ground, Jarvis measured between the framerails and axle housing to help center the rearend perfectly.

In addition to determining the side-to-side positioning of the rearend, the orientation of the upper control arms also determines the pinion angle. From Jarvis' experience, 2 degrees of pinion angle provides plenty of forward bite for A-bodies, as their four-links don't distort much under heavy acceleration. To achieve that angle, he shortened the upper control arms slightly from their baseline setting.

Project Olds' new 275/40R18 Nitto tires cleared the rear wheelwells, but just barely. Accurately centering the rearend helps maximize the available real estate in the stock tubs. Jarvis plans to set the cornerweights during final suspension setup, but for now, the rear ride height was set at 23.5 inches from the ground to the top of the wheelwell.

With the new control arms, braces, and coilovers in place, it was time to install DSE's 1.125-inch tubular rear sway bar. Unlike many factory bars that attach to the lower control arms, the DSE piece bolts to the frame. This keeps more vertical load on the inside wheel during cornering for enhanced grip. Since the preliminary ride height had already been set, Jarvis mocked the sway bar into position to help determine where the frame would have to be drilled for the endlink mounts. The bar was affixed to the rearend using supplied U-bolts torqued to 60 lb-ft.

The DSE endlinks swivel back and forth along two axis, which allows the sway bar to articulate freely and reduces binding. The upper and lower endlink bolts were tightened to 45 and 40 lb-ft, respectively. The sway bar features two mounting points, which enables fine tuning the rear end stiffness. The distance separating the two holes might not seem like much, but the basic tenets of sway bar design say that minimal changes in swing arm length yield dramatic changes in bar stiffness. DSE rates the bar stiffness at 507 lb/in when the front mounting holes are used, and 624 lb/in when the rear holes are used.

Using DSE's provided template, Jarvis drilled two 1/2-inch holes in the rear crossmember, each spaced 15.5 inches from the crossmember centerline. The endlink brackets were then affixed to the frame using 1/2-inch bolts and Nylok nuts torqued to 80 lb-ft.