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Adjustable Front Suspension Control
The GD401-11300A QA1 GM Pro Front Coil-Over System provides adjustable ride height and double-adjustable damping control for vehicle-specific GM front suspension applications. Its aluminum coil-over shocks and 11-inch, 300 lb./in. pigtail springs are designed for street performance, autocross, road racing, drag racing and street rod use.
Key Features
- GD401-11300A is the exact QA1 configuration described on this page
- Double-adjustable shock valving
- Front GM Pro Coil system
- Aluminum coil-over shocks
- 11-inch high-travel pigtail springs
- 300 lb./in. spring rate
- Fully threaded shock bodies for ride-height adjustment
- Sold as a pair
- Serviceable and rebuildable through QA1 authorized service centers
- Made in the USA
Fitment
| Application | Position | Restrictions |
|---|---|---|
| Buick, Chevrolet, Oldsmobile and Pontiac | Front | Vehicle-specific GM application. Verify year, model, engine, body style and suspension configuration before ordering. |
| 1967 Chevrolet Camaro | Front | The exact product appears in Camaro coil-over search results, but direct year-specific fitment is not confirmed in the supplied record. Verify application before ordering. |
| Chevrolet Camaro Z28 | Front | The exact product appears in Camaro Z28 coil-over search results, but direct model-specific fitment is not confirmed in the supplied record. Verify application before ordering. |
Specifications
| Detail | Value |
|---|---|
| Manufacturer | QA1 |
| Model | GD401-11300A |
| Part type | Front Coilover System |
| Vehicle position | Front |
| Shock adjustment | Double adjustable |
| Spring length | 11 inches |
| Spring rate | 300 lb./in. |
| Spring design | Pigtail |
| Shock construction | Aluminum |
| Ride-height adjustment | Threaded shock body |
| Quantity | Pair |
What's Included
- One pair of front Pro Coil systems, as identified for GD401-11300A
About QA1
QA1 develops adjustable suspension components for street performance, drag racing, autocross, road racing and street rod applications. Its Pro Coil systems are dyno tested, serialized and designed to be serviceable and rebuildable through authorized service centers.
FAQ
What is the GD401-11300A?It is a QA1 GM Pro Front Coil-Over System with double-adjustable damping, an 11-inch spring, a 300 lb./in. spring rate, a pigtail spring design and aluminum construction.
Is this coil-over system universal?No. It is a vehicle-specific GM front suspension application.
What type of damping adjustment does it use?The system uses independent double-adjustable shock valving for compression and rebound control.
What is the spring rate?The included spring rate is 300 lb./in.
How long are the springs?The springs are 11 inches long.
Is ride height adjustable?Yes. The fully threaded shock body allows ride-height adjustment.
How many coil-over systems are included?The product is sold as a pair.
Who should install this system?Installation should be performed by a qualified technician using appropriate spring-compression and vehicle-support equipment, followed by a professional wheel alignment.
Installation Instructions
- Confirm GD401-11300A matches the listed application and configuration before disassembly.
- Record the vehicle ride height before beginning work.
- Park the vehicle on a level surface, support it securely with a floor jack and jack stands, and remove the front wheels.
- Disconnect the sway-bar end links as required for access.
- Support the front suspension and use a suitable coil-spring compressor to relieve spring tension before separating suspension components.
- Do not remove a ball-joint castle nut until spring tension has been safely relieved. Separate the lower ball joint with an appropriate separator.
- Remove the original front shock mounts and lower shock mounts. On applicable GM cars, remove the factory control-arm welded shock-mount nuts or U-clips. Enlarge mounting holes only as required by the installation instructions.
- Install the QA1 spring seat and lock nuts in the specified position for the system. Lubricate the shock threads with anti-seize lubricant.
- Install each pigtail spring with the pigtail aligned to the upper spring-pocket recess when applicable.
- Install the supplied GM lower shock fasteners and reconnect the lower ball joint. Tighten suspension fasteners to the applicable factory specification and install a new cotter pin where required.
- Reconnect the sway-bar links and reinstall the wheels.
- Adjust ride height with the QA1 spanner wrench. Do not use pliers or other tools on the adjuster.
- Set the vehicle on the ground, settle the springs by carefully bouncing the vehicle, and recheck ride height.
- Tighten the ride-height lock nut after the desired height is established.
- Complete a professional wheel alignment after installation.
- Do not exceed 18 damping clicks and do not use the shock as a droop limiter.
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