Transform your 1967–1970 Mustang’s rear suspension with QA1’s complete bolt-in 4-link system, featuring a custom QA1 9-inch rear housing. This all-inclusive kit delivers modern handling, improved traction, and the durability to handle serious horsepower - all while retaining a clean, factory-style fit. Perfect for restomod builds and performance street cars, this setup eliminates the compromises of leaf-spring suspension for good.MODERN HANDLING FOR YOUR CLASSIC MUSTANG QA1’s triangulated 4-link system replaces leaf springs with a geometry-optimized setup that improves traction, stability, and ride quality. By eliminating axle wrap and keeping pinion angle consistent under load, your Mustang will launch harder, corner flatter, and drive smoother - whether you’re cruising or carving corners. SINGLE ADJUSTABLE COILOVERS This system includes QA1’s single adjustable shocks, offering 18 clicks of rebound and compression adjustment together. A single knob makes it easy to fine-tune comfort and performance, giving you complete control over how your Mustang rides and handles. BUILT TO HANDLE BIG POWER QA1’s fabricated 9-inch housing is designed to take abuse. Fully formed trailing arm brackets minimize flex, while 3” OD, ¼” wall axle tubes and 31-spline alloy axles provide the strength to handle up to 650 HP (housing rated to 800 HP). The result is a rigid, predictable suspension that’s ready for modern horsepower levels. RIDE HEIGHT ADJUSTABILITY Easily adjust ride height from factory level to 3” lower. Fine-tune your stance and handling without compromising geometry, tire clearance, or comfort - all with simple, tool-free adjusters. EASY INSTALLATION The QA1 4-link kit is designed for self-fixturing weld-in installation, ensuring accurate alignment with minimal fabrication. The included QA1 9” housing bolts in cleanly, providing a precise fit with QA1’s brackets and coilovers.
Application-specific fit for 1967–1970 Ford Mustangs
Includes drain plug, fill plug, vent port, and jack pad for easy serviceability
Weld-in installation with self-fixturing brackets for perfect geometry
Complete system includes 9” rear housing, triangulated 4-link, and coilover shocks
Single adjustable shocks with 18 clicks of rebound/compression control
Adjustable ride height: factory to –3”
Eliminates axle wrap and wheel hop for improved traction and control