UMI Performance · New
UMI Performance 78-88 GM G-Body Boxed Lower Control Arms
MPN 3021-B · Store SKU umi3021-B
Supplier stock checked 11/7/2026, 11:24:24 AM UTC. Adding a part does not reserve it.
Request a return within 30 calendar days after delivery. New parts must be unopened and unused.
Shipping & returns ↗This policy does not limit rights required by law.Free standard shipping on eligible parts orders of $100 or more. Oversized and freight items excluded. Fitment, taxes, availability and final totals are confirmed before payment.
Product details
Rear control arms are essential suspension upgrades for GM vehicles. Stock control arms are prone to bushing deflection and rusting, leading to traction loss and poor handling. Our boxed control arms offer improved performance for both weekend cruising and track use. The included polyurethane bushings outperform OEM rubber, enhancing ride quality and reducing traction loss. These direct bolt-on control arms minimize wheel hop, enhance cornering, and promote track consistency. They are designed with provisions for both stock and aftermarket sway bars, with reinforced sway bar holes for added durability. Constructed with 0.120" wall thickness rectangular tubing, CNC machined bushing holders, and MIG welded end caps for protection against road debris. Installation is straightforward, using OEM hardware and taking approximately 1 hour. Detailed installation instructions are included for convenience. Upgrade your GM suspension with boxed rear control arms for better traction and handling. Poly bushings reduce deflection, while reinforced sway bar mounts add strength. Bolt-on arms minimize wheel hop, improve cornering. Boxed rear control arms boost handling, traction, and durability.
Manufacturer fitment & guides
Check 3021-B against the manufacturer’s application information below.
Part-specific notes
- California Proposition 65: Y
