3039 – 1978-1988 GM G-Body Rear Upper Control Arms, Adjustable, Roto-Joints, 12-Bolt Swap

UMI Performance offers 12-bolt swap control arms designed specifically for a 1964-1972 GM A-Body 10-Bolt or 12-Bolt rear end to be bolted into a 1978-1988 GM G-Body, including popular models like the Monte Carlo, Malibu, El Camino, Regal, Grand National, Grand Prix, and Cutlass. These upper control arms are designed at the correct angle to attach to both the G-Body chassis and the A-Body rear end “ears,” making them essential for completing this swap successfully.

Using factory control arms in this swap can lead to rear end bind, incorrect driveline angles, and ultimately result in traction loss, vibrations, and unsafe handling. UMI Performance’s control arms are adjustable for easy on-car adjustability to set the correct pinion angle and allow for installation adjustments if necessary. They feature a durable construction with TIG welded 4140 chrome moly tube adaptors and Roto-Joints for unrestricted rear end movement, making them ideal for high-performance applications such as handling, auto cross, road racing, and drag racing.

The Roto-Joint technology utilized in these control arms allows for 28 degrees of total rotation and unrestricted suspension movement. The hard chrome plated spherical ball rotates in a delrin race to prevent suspension bind and improve traction while reducing wheel hop. The 4140 chrome moly material and hard chrome plating ensure wear resistance, while the delrin bushing provides high resistance against wear and maintains its physical properties for optimal performance.

UMI Performance’s Roto-Joint is adjustable and 100% rebuildable, allowing for easy maintenance and longevity. The optional spanner wrench can be used to tighten the adjuster ring and apply more pressure to the delrin race inside the Roto-Joint, ensuring continued performance. This spanner wrench is also used for disassembling the Roto-Joint for cleaning, inspection, and rebuilding, making it a valuable tool for maintaining UMI Performance products.