Delivering unmatched ride quality, superior grip, and modern handling for your 70-81 GM F-Body. The Speedtech Independent Rear Suspension (IRS) transforms your muscle car into a precision-handling machine. Designed with optimized geometry, high-strength materials, and track-tested performance, this system gives you the confidence to carve corners, launch harder, and enjoy a smooth ride—all in one package.
With up to 315mm tire clearance, precise camber control, and full coilover adjustability, this bolt-in IRS brings next-level performance to the street or the track—without major chassis modification.
MODERN RIDE QUALITY, MAXIMUM GRIP
Independent suspension arms allow each rear wheel to react individually to the road, maintaining optimal tire contact and drastically improving both cornering and comfort. The result? A compliant, composed ride with relentless grip and balance.
FULLY TUNABLE PERFORMANCE
Double-adjustable QA1 or JRi coilovers paired with optimized motion ratios let you dial in ride height, rebound, and compression to match your driving style—whether you’re cruising, autocrossing, or road racing.
WIDE TIRE FITMENT, ZERO COMPROMISE
This system is engineered for aggressive setups—fit up to a 315/30/18 rear tire with full suspension articulation. Built-in camber and toe adjustability help you fine-tune alignment for the perfect stance and optimal contact patch. (With mini-tubbed applications, a 355mm tire width has been used)
TRACK-TESTED STRENGTH
Using Strenx® high-strength steel, the IRS cradle and control arms maintain incredible rigidity while reducing weight. Precision TIG-welded components and reinforced pickup points deliver long-term durability under high-stress conditions.
WELD-IN INSTALLATION
This IRS is a true re-design to the rear end suspension and floor/housing. The entire assembly is engineered to line up within stock frame rails. With our over-head design as a featured element in the trunk space, it retains usable interior trunk space, making it ideal for builds where drivability and refinement are just as important as performance.
PROUDLY BUILT IN THE USA
Crafted with pride in the USA from premium materials, this system is built to handle serious performance demands without sacrificing ride quality or reliability.
