UMI Performance GBF350-1 G-Body Coilover Shock & Spring Lowering Kit 350lb Double Adjustable 1" Drop

The UMI Performance GBF350-1 is a complete shock and spring lowering kit for 1978–1988 GM G-Body vehicles, combining four Viking double adjustable shocks with a hybrid front coilover spring system and Hotchkis rear lowering springs. Designed for builders who want to tune their car for the street, strip, or corner carving without picking up a single tool, this bolt-in kit requires no welding and no spring compressor.

Kit Includes:

• (2) Front coilover shocks, double adjustable — hand built in Lakeville, Minnesota
• (2) Rear shocks, double adjustable — hand built in Lakeville, Minnesota
• (2) Front springs — 350 lb rate (250, 350, 450, or 550 lb options available)
• (2) Rear Hotchkis lowering springs with choice of 1" or 2" rear drop

Front Spring Rate Guide:

• 250 lb — 11" tall drag race springs; serious vehicle lightening required
• 350 lb — Small block cruise or drag race; some lightening required
• 450 lb — Small block cruise; big block drag race
• 550 lb — Small block performance handling; all big blocks except drag

Key Features:

• 0–3" adjustable front lowering range; 1" or 2" rear drop
• 19 independent compression and 19 rebound settings — 361 total tuning combinations
• Dial in street, strip, or corner carving handling at the turn of a knob — no tools required
• Lower ride height improves handling by reducing center of gravity and placing the upper A-arm at a more favorable angle
• Viking premium Made-in-USA springs — shot peened and coated for long-term durability
• Bolt-in installation — no welding required, no spring compressor needed up front
• Optional Spanner Wrench & Thrust Bearing Kit available for easier front height adjustment while shock remains mounted

Recommended Baseline Shock Settings:

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

The optional Spanner Wrench and Thrust Bearing Kit allows front ride height adjustments without removing the shock. The thrust bearing seats between the spring and spring perch, enabling smooth rotation during height changes. While not required for installation, this upgrade is strongly recommended for ease of adjustability.