UMI Performance GBF550-1 Shock & Spring Lowering Kit Double Adjustable Shocks 550lb 1" Drop

The UMI Performance GBF550-1 is a complete shock and spring lowering kit for GM G-Body vehicles, pairing four Viking double-adjustable shocks with a hybrid front coilover spring system and Hotchkis rear lowering springs. With moderately increased spring rates for improved handling, this bolt-in kit delivers a tunable, performance-oriented suspension setup suitable for street driving, drag strip duty, and corner carving.

Shock & Spring Configuration:

• (2) Front coilover shocks, double adjustable
• (2) Rear shocks, double adjustable
• (2) Front springs — choice of 250, 350, 450, or 550 lb/in spring rate
• (2) Rear Hotchkis springs with choice of 1" or 2" rear drop

Front Spring Rate Guide:

• 250 lb/in — 11" tall springs for drag race only; serious weight reduction required
• 350 lb/in — Small block cruise or drag race; weight reduction required
• 450 lb/in — Small block cruise or big block drag race
• 550 lb/in — Small block handling or all big blocks except drag race

Key Features:

• 0–3" adjustable front drop; 1" or 2" fixed rear drop
• Lowers center of gravity and places the upper A-arm in a more favorable geometry angle for improved handling
• Viking double-adjustable shocks feature 19 independent compression and 19 independent rebound settings (361 total combinations)
• Tune from street to strip to corner carving at the turn of a knob — no tools required
• Shocks hand-built in Lakeville, Minnesota
• Viking premium USA-made springs, shot-peened and coated for long-term durability
• Easy front height adjustment with optional Torrington thrust bearing kit and spanner wrench (sold separately)
• Bolt-in installation — no welding required and no spring compressor needed up front

Baseline Shock Settings (Starting Points):

• All-around street: 6C / 8R
• All-around corner carving: 10C / 12R
• Strip (drag): 6C / 2R front, 6C / 6R rear

Optional Spanner Wrench & Thrust Bearing Kit: The spanner wrench allows front ride height adjustments while the shock remains mounted. The thrust bearing kit sits between the spring and spring seat, allowing the seat to rotate on a bearing for significantly easier height changes. This accessory kit is strongly recommended but not required to complete the installation.