 The Chevelle factory four-link...  The Chevelle factory four-link system uses a pair of upper and lower control arms with the suspension supported by coil springs. The upper control arms are angled outward to locate the rear axle under the car, eliminating the need for a Panhard bar or a Watts link. |  This is a side view of a drag...  This is a side view of a drag race four-link system. While the Chevelle's upper arms are angled, the system operates very similarly to a drag race four-link. In the sidebar, we've extended the lines to indicate the instant center (IC). |  One of the first things you...  One of the first things you can do to improve traction is to lower the rear ride height until the lower control arm is parallel to the ground. Costing little, lowering the ride height shortens the distance from the rear axle to the instant center by increasing the down angle of the shorter upper control arm. |
 According to Global West,...  According to Global West, using a boxed lower control arm with a stiff polyurethane bushing can cause binding when the car is turned into a steep driveway. Eventually, this bind can create cracks in the lower-control-arm mounts in the chassis. |  Pinion angle is also crucial...  Pinion angle is also crucial to ultimate traction. Several companies make an adjustable upper control arm that allows you to quickly set the length. This is Currie's arm with a beefy 1-inch-diameter threaded shaft. |  Edelbrock offers a complete...  Edelbrock offers a complete rear setup for a Chevelle with rectangular tubular lower arms and adjustable uppers. The adjustable upper arm features a spherical bearing on the chassis end that articulates with a polyurethane bushing for the rear-axle side. |