UMI Performance AB8550-1 Double Adjustable Coilover Shock & Lowering Spring Kit

The UMI Performance AB8550-1 is a complete front coilover and rear shock/spring lowering kit engineered for GM A-Body muscle cars. Featuring four Viking double adjustable shocks hand-built in Lakeville, Minnesota, this bolt-in system delivers a broad range of tuning flexibility for street cruising, drag racing, and corner carving — all without welding or a spring compressor.

The hybrid front coilover system provides a 0–3 inch front drop with easy ride height adjustment via a threaded collar, while the rear offers a choice of 1 inch or 2 inch drop springs. Viking shocks feature 19 independent compression and 19 rebound settings (361 total combinations), allowing you to dial in your suspension character simply by turning the external knobs — no tools required.

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

What's Included:

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

Key Features:

• Viking shocks hand-built in Lakeville, Minnesota
• 19 compression + 19 rebound settings — 361 possible damping combinations
• 0–3" front lowering range; 1" or 2" rear drop selection
• Lowered center of gravity improves handling and upper A-arm geometry
• Premium USA-made springs, shot-peened and coated for long-term durability
• True bolt-in installation — no welding, no spring compressor required
• Optional Torrington thrust bearing kit and spanner wrench available for easier height adjustment (sold separately; strongly recommended)

Baseline Shock Settings (Reference):

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

The optional spanner wrench allows ride height adjustments with the shock remaining mounted. The optional thrust bearing kit, placed between the spring and spring seat, reduces friction during adjustment and is strongly recommended for ease of use, though neither is required to complete installation.