UMI Performance 65-66 GM B-Body Adjustable Upper Control/Trailing ArmUMI Performance offers one of the only on car adjustable control arms for the rear of the GM B Body vehicle. This rear upper control arm for the 65 66 GM B Body is an excellent solution when looking to replace the worn out factory set up. Our rear upper control arms are a direct replacement for the factory arms and are designed to minimize wheel hop, improve cornering and help track consistency. This control arm is on car adjustable and allows easy