[Stocker 2]

Cars such as a coil spring Mustang or Chevelle do not use a panhard arm because the rear control arms are set at an angle to the centerline of the car. The angle of those control arms stop any sway. Any coil spring car that has the control arms running almost straight forward needs a panhard arm to stop the body from swaying sideways and keep the rearend centered under the car.

Both type setups can take advantage of an "added" anti-rollbar which stops the body from rolling or torqueing over on the suspension. Lately a lot of coil spring GM cars like the Chevelle, GTO, GS Buick, etc have bolted a large tube between the lower control arms tying them together. This is a beefier takeoff on the factory bar that was on the some of the original performance cars. I was told this setup is accepted because it bolts to the lower control arms.