UMI Performance AB4550-1 Double Adjustable Coilover Lowering Kit with Viking Shocks 550lb Front Springs

The UMI Performance AB4550-1 is a complete front and rear coilover shock and spring lowering kit built around four Viking double adjustable shocks hand-built in Lakeville, Minnesota. The hybrid front coilover spring system delivers a 0–3" adjustable front drop, while the rear springs offer a choice of 1" or 2" lowering — giving you full control over ride height without welding or a spring compressor.

Viking shocks feature 19 independent compression and 19 rebound settings, allowing you to dial in your suspension from a comfortable street cruise all the way to aggressive corner carving or drag strip performance — all with a simple knob turn, no tools required. Lowering the ride height also places the upper A-arm in a more favorable geometry angle, improving overall handling dynamics.

Kit Includes:

• (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 springs — choice of 1" or 2" rear drop

Front Spring Rate Options:

• 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 recommended
• 450 lb/in — Small block street cruise; big block drag race
• 550 lb/in — Small block handling and all big block applications except drag race

Baseline Shock Settings (reference):

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

Spanner Wrench & Thrust Bearing Kit: The included spanner wrench adjusts vehicle ride height 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 adjustments. This kit is strongly recommended — height adjustment without the thrust bearing kit is not advised.

Viking Springs are premium USA-made, shot-peened, and coated for long-term durability. This is a true bolt-in installation — no welding required, and no spring compressor needed for the front.