QA1 5Q683-5 Twin Tube Circle Track Shock Stock Mount GM Mid & Full Size Rear 3C/5R

The QA1 5Q683-5 is a large-body, twin-tube circle track shock absorber designed for stock mount applications on GM mid and full-size platforms. Featuring a 3 compression / 5 rebound (3C/5R) valving configuration, this shock is engineered for racers who demand consistent, tunable performance on dirt and asphalt circle tracks.

Key Features:

• Twin-tube, zero gas pressure design delivers maximum grip on slick and dry-slick tracks where traction is at a premium
• Two-piece steel body construction makes disassembly and reassembly fast and straightforward for trackside rebuilds
• Laser-engraved, black-anodized closure nut keeps serial numbers and valving information clearly readable at the track or in the shop
• Upgraded seal kit minimizes leaks, especially in high-rebound valving applications
• Slip-fit compression tube design simplifies the rebuild process without special tooling
• Gland with relief cuts and hyper screw port makes the shock easy to fill and bleed during assembly
• Raw aluminum pistons minimize the dimensional variations common in anodized parts for more consistent valving
• Coil-over compatible with appropriate QA1 coil-over conversion kits (sold separately)
• Racer-rebuildable using available QA1 tuning and rebuild kits with basic hand tools

The 5Q Series (formerly the 51 Series) represents an updated platform with improved internals for greater performance. The stock mount configuration and large steel body make the 5Q683-5 a direct-fit solution for circle track builds where class rules require OEM-style mounting. Valving can be further customized using bleed shims or by drilling out bleeds for maximum tunability.