The 1963-1982 Control Arm Bushings cushion the area between the control arm and the mounting flange it attaches to on the car. These Bushings come in a set of 8. Poly Urethane Bushings retain steering/chassis geometry under severe cornering or during competitive driving much better than stock rubber materials.
Learn more from the following Mid America Motorworks Knowledge Library article:
Corvette and Why to Use Urethane / Polyurethane for Your Suspension