UMI Performance 3623 Rear Coilover Brackets for 1978-1996 GM B-Body Caprice RWD

Vehicle Fitment

• 1978-1996 Chevrolet Caprice (All Trims, RWD)
• 1994-1996 Chevrolet Impala SS (RWD)
• 1991-1996 Buick Roadmaster (All Trims, RWD)
• 1978-1985 Buick LeSabre (All Trims, RWD)
• 1977-1981 Pontiac Bonneville (All Trims, RWD)
• 1977-1981 Pontiac Catalina (All Trims, RWD)

Fitment Notes

• Brackets-only kit - coilover shocks and springs are not included; purchase separately or upgrade to the complete kit (PN 3623-1 for sedans with 200 lb/in springs, or PN 3623-2 for wagons with 250 lb/in springs)
• Upper mount requires drilling with a standard 3/8" drill bit - no welding required for the brackets themselves
• For sedan applications, UMI recommends a 200 lb/in coilover spring rate; for wagon applications, 250 lb/in is recommended
• Fits factory GM B-Body rear axle housing - confirm axle is stock or stock-diameter replacement before ordering

Features

• Converts factory coil spring rear suspension to a fully functional rear coilover setup, enabling independent ride height and damping adjustability
• Laser-cut steel brackets JIG-welded at UMI for precise fitment on factory GM B-Body rear axles with consistent geometry across all units
• Bolt-in double shear upper and lower mounting system - no welding required for bracket installation, preserving factory chassis integrity
• Compatible with Viking double-adjustable coilover shocks (used in UMI's complete 3623-1 and 3623-2 kits) and other industry-standard rear coilover shocks
• 100% designed and manufactured in the USA

Specifications

• Part Number: 3623
• Product Name: Rear Coilover Conversion Brackets - 1978-1996 GM B-Body
• Installation: Bolt-in double shear upper and lower mounts; upper mount requires 3/8" drilling
• Bracket Construction: Laser-cut steel, JIG-welded
• Recommended Spring Rate - Sedan: 200 lb/in
• Recommended Spring Rate - Wagon: 250 lb/in
• Compatible Axle: Factory GM B-Body rear axle housing
• Country of Origin: Made in the USA
• Complete Kit Options: PN 3623-1 (sedan, 200 lb/in), PN 3623-2 (wagon, 250 lb/in)

Included Components

• 1x Set of UMI Rear Coilover Conversion Brackets (PN 3623)
• 1x Hardware/installation kit

Product Description

The UMI Performance 3623 is a bolt-in rear coilover conversion bracket kit engineered for the 1978-1996 GM B-Body platform, covering the Chevrolet Caprice, Impala SS, Buick Roadmaster, Buick LeSabre, Pontiac Bonneville, and Pontiac Catalina. The brackets replace the factory coil spring rear suspension setup with a coilover-compatible mounting system, enabling the use of adjustable coilover shocks for independent control of ride height and damping. Constructed from laser-cut steel and JIG-welded at UMI's Pennsylvania facility, the brackets are precision-fitted for factory GM B-Body rear axle housing dimensions without requiring cutting, fabrication, or welding to the chassis.

Installation uses a bolt-in double shear upper and lower mounting system; the only modification required is drilling the upper mount location with a standard 3/8" drill bit. This brackets-only kit is ideal for builders who already have coilover shocks on hand, or who want to select their own dampers. For a complete plug-and-play solution, UMI offers the 3623-1 (sedan, 200 lb/in Viking double-adjustable shocks) and 3623-2 (wagon, 250 lb/in) full coilover kits. Designed and manufactured 100% in the USA.