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Mustang II Front Coil-Over Conversion Shock for Hot Rods and Classic Fords
The QA1 QAPMS303 MS303 Pro Front Coil-Over Shock is purpose-built for 1974-1978 Ford Mustang II front suspension setups and the countless custom hot rods, street rods, and kit cars that have adopted Mustang II front clip geometry. Using a 7/16 inch lower bushing mount, the QAPMS303 drops directly into Mustang II-style spindles and control arms with no fabrication. The MS303 shock body is crafted from lightweight billet aluminum, features 18 single-adjustable valving positions, and a fully threaded body for 0 to 2 inches of ride height adjustment. At 7.88 inches compressed and 11 inches extended, the QAPMS303 is sized for proper travel geometry within Mustang II front suspension packaging. Sold as a single shock without springs. Every QA1 MS303 is 100% dyno tested, serialized, and backed by QA1's Limited Lifetime Warranty.
Key Features
- 7/16 inch lower bushing mount for direct fitment on Mustang II-style front suspensions
- Single adjustable valving with 18 settings for street, drag, or performance tuning
- Lightweight billet aluminum shock body for reduced unsprung weight
- Fully threaded body allows 0 to 2 inches of front ride height adjustment
- 7.88 inch compressed length, 11 inch extended length for Mustang II geometry
- Bolt-in installation at stock Mustang II mount locations, no welding required
- 100% dyno tested and individually serialized at QA1's Minnesota facility
- Serviceable and rebuildable by QA1 Authorized Service Centers
- Made in the USA
- Limited Lifetime Warranty from QA1
Fitment
| Year Range | Make | Model |
|---|---|---|
| 1974-1978 | Ford | Mustang II |
| 1975-1980 | Ford | Pinto |
| N/A | Various | Custom hot rods and street rods using Mustang II front clip |
Specifications
| Detail | Value |
|---|---|
| Part Number | QAPMS303 / MS303 |
| Position | Front |
| Shock Type | Pro Coil, Billet Aluminum |
| Valving | Single Adjustable, 18 settings |
| Extended Length | 11 inches |
| Compressed Length | 7.88 inches |
| Lower Bushing | 7/16 inch |
| Ride Height Adjustment | 0 to 2 inches lowered |
| Body Material | Billet Aluminum |
| Springs Included | No (shock only) |
| Made In | USA |
| Warranty | Limited Lifetime |
| UPC | 806990096036 |
What's Included
- 1x QA1 MS303 Pro Front Coil-Over Shock Absorber (7/16in bushing)
- Installation hardware
About QA1
QA1 is a Minnesota-based performance suspension manufacturer specializing in coil-over shocks, rod ends, and driveshafts for classic American vehicles and custom builds. The MS303 is part of their Mustang II-specific Pro Coil lineup, designed to make the popular Mustang II front suspension platform perform at the highest level. Every QA1 aluminum shock is 100% dyno tested, serialized, and designed to be rebuilt rather than replaced.
Frequently Asked Questions
What vehicles does the QAPMS303 fit?The QAPMS303 MS303 is designed for 1974-1978 Ford Mustang II front suspension applications. It is also widely used in custom hot rods, street rods, and kit cars that utilize Mustang II front clip geometry, which is one of the most popular front suspension swap packages in the custom car industry. The 7/16 inch lower bushing interfaces directly with Mustang II-style lower spindle mounts.
Does the QAPMS303 come with springs?No. The QAPMS303 is the shock body only. QA1 Pro Coil springs must be purchased separately to complete the coil-over assembly. Spring rate selection depends on your front-end weight. Consult QA1's spring rate guide or their technical support team at QA1.net for the correct spring rate for your specific application.
Why is the Mustang II front suspension used in custom builds?The Mustang II front clip was designed in the early 1970s as a compact, lightweight IFS system with modern geometry compared to 1950s-1960s designs. Custom builders adopted it for pre-1965 cars, trucks, and rods because it offers rack-and-pinion steering, disc brakes, and geometry that can be adapted to almost any chassis with commercially available crossmembers and brackets. The QAPMS303 gives these builds proper adjustable coil-over performance.
How does the single adjustable valving work on the MS303?The MS303 features 18 simultaneous compression and rebound valving positions adjusted via the knob at the top of the shock body. Lower numbers give softer, more compliant damping for street cruising. Higher numbers firm up response for spirited driving or autocross. QA1 recommends starting in the middle range (position 9 of 18) and tuning from there based on road feel.
What spring rate should I use with the QAPMS303?Spring rate selection depends on front-end weight and intended use. Most Mustang II-based street car builds run 300 to 450 lb/in front springs. High-performance and track-focused builds may run stiffer rates. QA1 offers their Pro Coil springs in multiple rates specifically sized for the MS303 shock travel dimensions. Contact QA1 technical support for a recommendation based on your build.
Is the QAPMS303 rebuildable?Yes. Every QAPMS303 shock is individually serialized and designed to be serviced and revalved by QA1 Authorized Service Centers. This makes the QAPMS303 a long-term investment rather than a consumable part, which is especially valuable in custom builds where matching replacement shocks may be difficult to source years down the road.
What is the ride height adjustment range on the MS303?The QAPMS303 provides 0 to 2 inches of front ride height adjustment via the fully threaded shock body. Turning the lower spring perch up or down on the threads changes the installed ride height. A spanner wrench (QA1 P/N T114W or T115W) is required to make this adjustment.
How does the 7/16 inch bushing on the QAPMS303 compare to other QA1 shocks?The 7/16 inch lower bushing on the QAPMS303 is matched to the lower spindle bolt diameter used in Mustang II-style front suspension designs. Other QA1 Pro Coil shocks (such as those for GM applications) use different lower mount configurations. Always confirm your crossmember and spindle lower mount diameter before ordering to ensure proper fitment.
What warranty does the QAPMS303 carry?The QAPMS303 is covered by QA1's Limited Lifetime Warranty for as long as the original purchaser owns the vehicle. Register your warranty at QA1.net/Warranty after installation. The warranty covers defects in materials and workmanship under normal performance use conditions.
Installation Notes
- Verify that your crossmember, spindles, and control arms are fully compatible with QA1 MS303 mount dimensions before starting
- Safely lift and support the vehicle, with front suspension hanging freely at full droop
- Thread the spring perch collar to your desired ride height starting position before assembly
- Slide the QA1 Pro Coil spring onto the shock body and seat it on the lower perch
- Install the QAPMS303 at the upper mount and lower 7/16 inch bushing mount, torquing hardware to your crossmember manufacturer's specification
- Set final ride height using spanner wrench (QA1 P/N T114W or T115W) with weight on the suspension
- Start valving at position 9 of 18 and test drive before adjusting further
- Check and set alignment to your build's target caster, camber, and toe specifications after installation
WARNING: This product can expose you to chemicals including lead and phthalates, which are known to the State of California to cause cancer and reproductive harm. For more information go to www.P65Warnings.ca.gov.
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