QA1 R904S 9in. Housing for 67-70 Mustang with QA1 4-Link

Already running one of QA1’s 4-Link Suspension Kits on your 1967–1970 Mustang? Upgrade your build with QA1’s fabricated 9” rear housing — engineered for seamless integration, improved strength, and simplified serviceability. This housing is purpose-built to withstand modern horsepower levels while maintaining precise suspension geometry and a clean, bolt-on installation.

ENHANCE YOUR EXISTING QA1 4-LINK

QA1’s 9” rear housing is designed to bolt directly to QA1 4-link systems, eliminating the need for custom fabrication. It features fully formed trailing arm brackets that reduce flex under hard acceleration and cornering, ensuring your suspension performs consistently under load. Whether you’re upgrading your street car or finishing a restomod project, this housing provides the perfect combination of strength, alignment precision, and OEM-level fit.

FEATURES & BENEFITS

• Fabricated steel center section engineered for maximum rigidity and long-term durability
• Fully formed trailing arm brackets reduce flex for consistent suspension geometry
• Heavy-duty 3” OD, ¼” wall axle tubes for high-performance street and strip builds
• 31-spline 1541H alloy axles rated for up to 650 HP; housing rated to 800 HP
• Big Ford “New Style Torino” flanges (2.5” axle offset) for wide brake compatibility
• Standard 5x4.5” bolt pattern fits popular Ford wheel options
• Integrated drain plug, fill plug, vent port, and jack pad for simplified servicing
• ½” x 3” wheel studs for secure wheel fitment
• Factory wheel mounting surface width for proper tire clearance – 1967–1970: 59 3/8”
• Durable semi-gloss powder coat finish resists corrosion and looks great
• Includes T-bolts, housing studs, and roller bearings for smooth, quiet operation

EASY INSTALLATION & SERVICEABILITY

QA1’s bolt-in design means no cutting or welding is required. Every detail - from the formed brackets to the integrated jack pad and fill/drain ports - is built to simplify installation and maintenance. If your Mustang already runs a QA1 4-link system, this housing bolts directly in for a precise, trouble-free upgrade.

HELPFUL SPECIFICATIONS

• Fits QA1 4-Link kits for 1967–1970 Ford Mustangs
• Factory wheel mounting surface: 59 3/8”
• Big Ford “New Style Torino” flanges with 2.5” axle offset
• 5x4.5” bolt pattern (standard Ford fitment)
• ½” x 3” wheel studs
• 2.770” hub diameter
• Requires third member for Ford 9” housings with 31-spline axles
• Axle Shaft Splines: 31
• Width at wheel mount surfaces: 59 3/8in
• Brake Flange: Big Ford "New Style Torino"
• Brake Offset: 2.5"
• Bolt Pattern: 5x4.5 in