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.
Features:
- Complete 4-link system with QA1 9” Ford rear housing
- Application-specific fit for 1964–1966 Ford Mustangs
- Single adjustable shocks with 18 settings of rebound/compression control
- Adjustable ride height: factory to –3”
- Triangulated 4-link design eliminates axle wrap and wheel hop
- Fabricated center section and 3” OD, ¼” wall axle tubes for maximum strength
- 31-spline 1541H alloy axles rated up to 650 HP; housing rated to 800 HP
- Big Ford “New Style Torino” flanges for easy brake compatibility
- 5x4.5” bolt pattern fits popular Mustang wheel options
- Weld-in installation with self-fixturing brackets for easy alignment
- Made in the USA with premium materials and hardware
Notes:
- Fits 1964–1966 Ford Mustangs
- Designed to work exclusively with the included QA1 9” housing
- Weld-in installation required
- Factory wheel mounting surface: 57 3/8”
- Compatible with Big Ford “New Style Torino” brakes
- 31-spline, 5x4.5” bolt pattern
WARRANTY / DISCLAIMER
QA1 warrants that the products will be free from defects in material and workmanship for one year from date of sale to the original purchaser. A limited lifetime warranty is offered on select shock absorbers. For registration and more information on the limited lifetime warranty, please visit https://www.qa1.net/Warranty. QA1 makes no other warranty of any kind, express or implied. QA1 shall have no obligation under the foregoing warranty where the defect is the result of improper or abnormal use, your negligence, vehicle accident, improper or incorrect installation or maintenance, nor when the product has been repaired or altered in any way. QA1's liability in the case of defective products subject to the foregoing warranty shall be limited to the repair or replacement, at QA1's option, of the defective products. Consequential or incidental damages are not recoverable under this warranty. Some states do not allow the exclusion or limitation of incidental or consequential damages, so the above limitation or exclusion may not apply to you. This warranty gives you specific legal rights, and you may also have other rights that vary from state to state.
- QA1, in its sole discretion, shall determine whether or not any Eligible Product is defective or otherwise covered by this warranty.
- If the Eligible Product fails to perform properly due to defective materials or workmanship, QA1 will at its option either (i) repair the Eligible Product without charge, or (ii) replace the Eligible Product. If the Eligible Product is no longer available, QA1 will replace the Eligible Product with an equivalent product. No refunds will be provided.
- The warranty provided by QA1 does NOT apply if the Eligible Product fails to perform:
- due to cosmetic wear and tear from normal use;
- due to improper or abnormal use, abuse, neglect, negligence, vehicle accident, insufficient travel, improper or incorrect installation or maintenance; or
- when the Eligible Product has been repaired, replaced, substituted or altered in any way, or if used with parts other than genuine parts of QA1.
- QA1 is not responsible for installation or removal labor, or for any other repair charges associated with the Eligible Product.
- Customer pays shipping to QA1 for final determination on eligibility. Any repaired or replaced Eligible Product will be returned to customer excluding freight cost.
- QA1 shall not be liable for the loss of use of the Eligible Product, loss of time, inconvenience, commercial loss or any other indirect, consequential, special or incidental damages due to breach of the above limited lifetime warranty. QA1 makes no warranties of any kind, express or implied, other than as herein expressly provided, and specifically disclaims the implied warranties of merchantability and fitness for a particular purpose. Notwithstanding anything set forth herein to the contrary, QA1’s liability hereunder shall be limited to the purchase price of the Eligible Product.
In order to be eligible for service under this warranty, you must return the defective part to QA1 together with a RMA. number issued from QA1. Tag each item with the part number and the specific explanation of defect. We will inspect the part and determine: a) if it is eligible for repair or replacement; and, b) if so, whether to repair or replace it. All returns must be shipped prepaid to: QA1 Precision Products, Inc., RMA#__________, 9574 217th Street West, Lakeville, MN 55044.
THE BUYER UNDERSTANDS AND EXPRESSLY RECOGNIZES that racing parts, specialized street rod equipment, rod end bearings, and ALL parts and services sold by QA1 are exposed to many and varied conditions due to the manner in which they are installed and used. BUYER ACKNOWLEDGES that QA1 does not have full knowledge of the intended use of the goods, and BUYER WILL DEFEND AND INDEMIFY QA1 upon demand against all claims, actions, liability, loss and expense (including investigating expense and attorney fees incurred in litigation or because of threatened litigation) for any loss, damage or injury, either to a person or to property, resulting from the direct or indirect use of any QA1 products or inability by the buyer to determine proper use or application of QA1 products. With the exception of the limited liability warranty set forth above, QA1 SHALL NOT BE LIABLE FOR ANY CLAIMS, DEMANDS, INJURIES, DAMAGES, ACTIONS, OR CAUSES OF ACTION WHATSOEVER TO BUYER ARISING OUT OF OR CONNECTED WITH THE USE OF ANY QA1 PRODUCTS. MOTORSPORTS ARE DANGEROUS; AS SUCH, NO WARRANTY OR REPRESENTATION IS MADE AS TO THE PRODUCT'S ABILITY TO PROTECT THE USER FROM INJURY OR DEATH. THE USER ASSUMES THAT RISK.
