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Suspension and Components Suspension Kits

QA1 Precision Products, Inc

QA1 64-66 Ford Mustang Rear Suspension Conversion System - 9in Housing Single Adj. 130lb/in

$4,677.22 $4,313.43 Save $363.79

SKU: Q00B R123-130S

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INSTALL DIFFICULTY
DIY PRO SHOP

Moderate — 2–4 hours

Description

Part #: R123-130S

Upgrade your classic Mustang's rear suspension with QA1's complete 4-link system, featuring a custom QA1 9" rear housing. Designed specifically for 1964-1966 Mustangs, this all-in-one solution delivers modern handling, improved traction, and the strength to handle serious power. Whether you're building a street-driven restomod or a pro-touring performer, this kit is built to transform how your Mustang drives and feels. MODERN HANDLING, CLASSIC FIT QA1's triangulated 4-link replaces the factory leaf springs with a fully adjustable, geometry-correct rear suspension system. It dramatically improves traction, cornering, and ride quality by eliminating axle wrap and maintaining consistent pinion angle under load. The included QA1 9" rear housing ensures a perfect fit and the durability needed for today's performance builds. SINGLE ADJUSTABLE COILOVERS This kit includes QA1's single adjustable shocks, offering 18 clicks of combined rebound and compression adjustment. With one knob, you can easily fine-tune ride comfort and performance for your preferred driving style - from smooth street cruising to spirited cornering. STRONG, RELIABLE, AND READY FOR POWER The included QA1 9" housing features fully formed trailing arm brackets, a fabricated steel center section, and heavy-duty 3" OD axle tubes. Together, they create a rigid foundation capable of handling up to 800 horsepower. Matched 31-spline alloy axles ensure strength and smooth operation mile after mile. RIDE HEIGHT & ADJUSTABILITY Easily dial in your stance with adjustable ride height from factory level to 3" lower. This flexibility lets you fine-tune your Mustang's appearance and performance without compromising geometry or drivability. EASY INSTALLATION This kit comes complete with everything you need for a straightforward installation - from the housing and brackets to shocks and hardware.

Features:

  • Application-specific fit for 1964-1966 Ford Mustangs
  • Complete rear suspension system: 9" housing, 4-link, and coilovers
  • Single adjustable shocks with 18 settings of rebound/compression control
  • Adjustable ride height from stock to -3"
  • Eliminates wheel hop and axle wrap
  • Heavy-duty fabricated 9" housing rated to 800 HP
  • 31-spline 1541H alloy axles rated to 650 HP
  • Big Ford "New Style Torino" flanges with 2.5" axle offset
  • 5x4.5" bolt pattern for wide wheel compatibility
  • Includes drain plug, fill plug, vent port, and jack pad for easy service
  • " x 3" wheel studs for better fitment with aftermarket wheels
  • Durable semi-gloss powder coat finish
  • Weld-in installation with self-fixturing brackets for perfect alignment

1964-1966 Ford Mustang

This product may expose you to chemicals known to the State of California to cause cancer, birth defects, or other reproductive harm.

MIA's Description

The QA1 R123-130S is a Four-Link Rear Suspension System with a 9-inch housing designed specifically for 1964-1966 Ford Mustang models, offering modern handling, adjustability, and strength with single-adjustable coilovers and a customizable ride height.

Fitment

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Specifications

BrandQA1 Precision Products, Inc
Part NumberQ00B R123-130S

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Built for enthusiasts. Every order is backed by our 30 day return window on eligible items. Unused and uninstalled products may be returned with approved RMA and no restocking fees when received in new condition. Orders placed through the MOTORMIA app with a complete build qualify for our Fitment Guarantee — free return shipping if the part doesn’t fit your exact setup. The guarantee covers fit only; installation must follow manufacturer instructions, and we recommend a qualified shop for parts marked Difficulty 4–5.

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