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Replace the rear leaf spring layout with an adjustable torque arm and Watts link system.
QA1 part R121-200 is engineered for short wheelbase 1973-1979 Ford F-100 and F-150 trucks with a compatible iron third member.
Key Features
- Torque arm and adjustable Watts link rear suspension design
- Single adjustable shocks with 18 damping positions
- 200 lb/in coil springs
- Adjustable lower trailing arms
- Provides an adjustable 4 to 7 inch drop
- Bolt in installation with supplied brackets and hardware
Fitment
| Years | Make | Model | Body Requirement | Axle Requirement |
|---|---|---|---|---|
| 1973-1979 | Ford | F-100 | Short wheelbase only | 9 inch axle with iron third member |
| 1973-1979 | Ford | F-150 | Short wheelbase only | 9 inch axle with iron third member |
Specifications
| Detail | Value |
|---|---|
| Manufacturer Part Number | R121-200 |
| Position | Rear |
| Adjustment | Single adjustable |
| Spring Rate | 200 lb/in |
| Drop Range | 4 to 7 in |
| Axle Compatibility | Stock or direct fit 9 inch axle with iron third member |
| Construction | Powder coated tubular components |
| Origin | Made in USA |
What's Included
- R121-200: Watts link
- Torque arm
- Adjustable lower trailing arms
- Bracket mounts
- Single adjustable shocks
- 200 lb/in springs
- Installation hardware
About QA1
QA1 develops adjustable suspension systems and components for classic trucks, muscle cars, and performance vehicles.
FAQ
What is the R121-200?
It is the exact manufacturer part number for this rear suspension system.
Does it fit long bed trucks?
No. This system is for short wheelbase trucks only.
Can it be used with an aluminum third member?
No. Aluminum third members are not compatible.
What axle is required?
Use the stock 1973-1979 Ford 9 inch axle with an iron third member or a direct fit aftermarket equivalent.
What spring rate is included?
The kit includes 200 lb/in springs.
How much can it lower the truck?
The system provides an adjustable 4 to 7 inch drop.
Are the shocks adjustable?
Yes. The supplied shocks are single adjustable with 18 damping positions.
Does the kit require welding?
No. This system is designed as a bolt in installation.
Installation Instructions
- Before installing R121-200, support the vehicle securely and unload the rear suspension before beginning.
- Install the supplied brackets, torque arm, trailing arms, Watts link, shocks, and springs following QA1 instructions.
- Apply anti-seize to threaded shock bodies, set ride height only while unloaded, then complete a professional alignment and fastener check.
QA1
QA1 suspension parts are stocked at Black Ops Auto Works for American muscle cars and classic trucks. Shop coilover kits, shock absorbers, springs, handling kits, four link systems, sway bars, strut kits, rod ends, and suspension hardware for the Mustang, Camaro, Corvette, Challenger, Charger, and GM B-Body, F-Body, and G-Body platforms. Every product is filterable by year, make, model, trim, and drivetrain so the correct part ships the first time. Black Ops Auto Works carries 536 QA1 SKUs across coilovers, shocks, springs, and handling kit categories. What This Brand Covers QA1 is a suspension manufacturer known for adjustable coilover systems, shock absorbers, and complete handling kits built for muscle cars, classic trucks, drag cars, and pro touring builds. The lineup covers everything from single component shock replacement to full vehicle handling packages. Brand Focus QA1 concentrates on American muscle car and classic truck platforms, with deep coverage of GM, Ford, and ...
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