QA1 DS501-12250 HD Pro Rear Weld-In Coilover Conversion Kit, Single Adjustable, 250lb/in Spring, 3.0" Axle

The QA1 DS501-12250 HD Pro Rear Weld-In Coilover Conversion System is a heavy-duty, complete rear suspension upgrade for cars and trucks running a 3.00" axle tube. Engineered for vehicles with a rear axle weight of 1,700–2,600 lbs., this kit provides everything needed to convert to a coilover rear suspension setup with professional-grade components and up to 9" of total ride height adjustability.

At the heart of the system are QA1's single adjustable Proma Star coilover shocks, featuring a single dial that cycles through 18 valving positions — simultaneously adjusting both compression and rebound — for precise, on-the-fly suspension tuning suited to street cruising or aggressive driving alike.

Key Features:

• Designed for vehicles with 1,700–2,600 lb. rear axle weight
• Compatible with 3.00" diameter axle tubes — welding required
• Up to 9" total ride height adjustability: ¾" increments via axle-mounted brackets plus fine-tuning via coilover shock
• Double shear bracketry for increased strength and rigidity
• 250 lb/in. spring rate for street and race applications
• Single adjustable Proma Star shocks with 18 compression/rebound valving settings
• Weld-in tube: 1-5/8" O.D. x .095" wall x 40" long tubular upper shock mount
• 100% dyno tested and serialized shocks
• Revalveable and rebuildable by QA1 factory or authorized service centers
• Requires QA1 spanner wrench T114W or T115W (sold separately)
• Best-in-class lifetime warranty on shocks (registration at QA1.net/warranty required)
• Made in the USA — manufactured in Lakeville, Minnesota

What's Included:

• (2) Single adjustable Proma Star DS501 coilover shocks
• (2) 250 lb/in. coilover springs
• (1) 40" weld-in upper shock mount tube (1-5/8" O.D. x .095" wall)
• All axle mount bracketry and mounting hardware

The DS501-12250 is ideal for drag racing, street performance, and street rod builds where reliable, tunable rear suspension performance is essential. The straightforward weld-on design minimizes fabrication time and gets your build on the road faster.