6425 – 1973-1987 GM C10 Rear 4-Link Suspension Kit
Installation Pictures
PRODUCT DESCRIPTION
Upgrade your classic truck’s suspension and handling with the UMI Performance C10 4-Link Suspension Kit—the premier solution for 1973-1987 Chevy and GMC squarebody owners looking to unleash the full potential of their ride.
73-87 C10 4 Link Rear Suspension Kit: Transform Your Squarebody
The UMI 6425 kit replaces the outdated leaf spring setup on your C10 with a race-inspired 4-link rear suspension system featuring unequal length trailing arms, an adjustable panhard bar, and high-performance Viking coilovers (add-on). Engineered for serious street and pro-touring enthusiasts, this suspension kit is tuned for maximum traction, precision alignment, and stellar ride comfort. Whether it's weekend cruising, autocross, or high-power builds, the UMI 4-link delivers proven results.
Key Features & Benefits
-
Race Inspired, Unequal Length Trailing Arms:
Provides superior axle control, reduced wheel hop, and enhanced traction compared to factory leaf springs, optimizing your C10’s suspension geometry for both street and performance driving. -
Fully Adjustable Panhard Bar:
Lets you easily center your rear axle after lowering or height changes by fine-tuning bar length. Adjust mounting height at the frame or axle to dial in your rear roll center—precisely tune handling and body roll to your preferences. -
Instant Center Adjustable Chassis Mounts:
Quickly change suspension pickup points to tune anti-squat, instant center location, and weight transfer under acceleration, giving you the edge for drag strip launches and corner exit grip. -
Heavy Duty Crossmember Included:
Designed for strength and rigidity, maintaining chassis integrity under aggressive loads, and tying the entire rear suspension assembly together. Add optional PN 6426 rear frame brace for additional frame strengthening. -
Available Fuel Tank Relocation:
Integrated crossmember mounting points for optional PN 6428 fuel tank relocation kit. -
Light Fabrication Required:
Straightforward installation with basic fabrication such as drilling out old spring perch rivets and trimming for the included notch kit—no guesswork or excessive modifications required. Simply bolt-on after completing the frame modifications. - Aftermarket Rear Ready:
The included lower rear-end panhard bar mounting bracket is specifically designed to clear most aftermarket rears with additional center section bracing. -
Race Proven, Built in the USA:
Trusted on race tracks and by performance builders across the USA, every UMI 4-link kit is engineered, manufactured, and tested right here in America from the best materials.
Double Adjustable Viking Coilovers (Optional add-on):
The Viking Performance C209-W shock is a double adjustable coil-over shock designed for street and competition use, featuring independent compression and rebound tuning for optimized performance and ride quality. Perfect for performance C10 suspension upgrades seeking both drivability and control.
Coilover Key Features:
-
19 distinct adjustment positions for each knob means users can dial in precise ride quality and performance.
-
Premium bearing mounts with stainless steel races enhance durability and misalignment capabilities, outperforming basic nylon/poly bushings.
- 12DP225 225 lbs/inch spings are premium coil-over spring designed for high-performance suspension setups, offering both strength and reduced weight for demanding street or competition builds.
- Contact sales for additional customized spring options based on your application
PRODUCT FEATURES
- Unequal length trailing arms for maximum performance
- Adjustable panhard bar for axle centering and roll center tuning
- Double adjustable, race-proven Viking coilovers
- Heavy-duty crossmember for strength and regidity
- Works with factory or UMI relocated fuel tanks
- Minimal fabrication for installation
- 6 inch drop nominal ride height range
- Made in the USA, track tested for confidence
PRODUCT FAQ
Q: What is a 4-link suspension kit and why upgrade my C10?
A: A 4-link suspension kit replaces your C10’s original leaf springs with a system using four control arms to precisely position and control the rear axle. Upgrading provides:
- Improved traction and stability: Reduced wheel hop and better power transfer.
- Superior handling and ride comfort: Isolates springing from axle location, enabling the use of coilovers.
- Full adjustability: Tune ride height, pinion angle, and handling to your driving style.
- Increased suspension travel and articulation- Especially for road racing and autocrossing
Q: What do the adjustable upper and lower control arms do?
A:
- Axle fore-aft position: Adjusting the length of the lower arms shifts the axle forward or backward to fine-tune wheelbase or tire clearance.
- Pinion angle: Lengthening or shortening the upper arms changes the driveshaft/pinion relationship for reduced vibration and optimal power delivery.
- Instant center and anti-squat: Altering the lengths affects the suspension’s instant center, which changes how the truck handles squat and traction under acceleration.
Q: How do mounting point heights affect performance?
A:
- Anti-squat geometry: Raising or lowering the front or rear mounts of the control arms changes how the suspension resists squatting under hard acceleration. Higher anti-squat gives better launch traction; lower anti-squat offers a smoother ride.
- Roll steer: Mounting heights impact how the rear axle steers during suspension movement, which can influence cornering stability.
- Instant center location: Both length and mounting height adjustments are crucial for dialing in launch characteristics, weight transfer, and cornering grip.
Q: What does an adjustable panhard bar do?
A:
- Side-to-side axle centering: Adjusting the bar’s length moves the axle laterally to re-center it after changing ride height.
- Roll center tuning: Changing the mounting height of the bar (at the frame or axle) raises or lowers the rear roll center, affecting body roll and handling balance.
Q: What are the benefits of spherical rod ends in this kit?
A:
- Precision: Virtually zero flex gives exact axle location and repeatable alignment under hard driving.
- Superior articulation: Multi-axis rotation reduces binding during suspension travel.
- Easy adjustment: Threaded ends make dialing in pinion angle or axle position simple.
- High strength: Handles performance driving and high horsepower loads.
- Immediate feedback: No bushing squish—suspension response becomes sharp and direct.
Q: Can I adjust ride height with this kit?
A: Yes! Our C10 4-link kit allows for easy adjustment of ride height with the Viking Performance coilovers (optional add-on).
Q: What driving style are the optional Viking Performance Coilovers with the 225/lb springs tuned for?
A: The optional Viking Performance coilovers with 225 lb/in springs are typically tuned for comfortable and controlled street driving, mild performance, and vehicles that prioritize ride quality and moderate handling over extreme track or drag-strip conditions. Additional spring options are available through our sales department.
Q: Does the UMI 4-Link C10 kit work with aftermarket rear-ends like Quick Performance?
A: Yes! Our lower panhard bar rear-end mounting bracket has been designed with aftermarket rear ends in mind. It works with Quick Performance rears and fits most aftermarket rears with center section flanges that are equal to or smaller than those on Quick Performance rears.
Q: Will I need to weld or modify my truck?
A: Yes, cutting of the frame for the C-notch and removal of spring perches is required. Our C10 4-Link kit does not require welding and is 100% bolt on after frame modifications.
Q: What makes this kit better than simply lowering my C10 with leaf springs?
A: Unlike leaf springs, a 4-link:
- Maintains optimal axle alignment and tire contact during aggressive acceleration, braking, and cornering.
- Offers individualized geometry adjustment for handling and traction.
- Reduces unsprung weight for better suspension response.
- Allows for more aggressive ride height drops without sacrificing performance or reliability.
THIS PRODUCT FEATURES
Designed & Manufactured in the USA
Durable Powder-Coat
North American Raw Materials
Precision Laser Cut Components
Precision Welds
Mounting Hardware
HD Crossmember
Adjustable Panhard Bar
HD Control Arm Axle Mounts
HD Panhard Bar Axle Mount
Integrated Upper Panhard Bar Mount
Upper Shocks Mounts
Upper Control Arm Axle Mounts
Double Adjustable Control Arms
Spherical Rod Ends
Front Frame Mounts
Thrust Bearing & Spanner Wrench
6425 - 1973-1987 GM C10 Rear 4-Link Suspension Kit
About Viking Performance
Viking Performance, Inc. specializes in high-performance double adjustable shock absorbers and related products. Founded in 2011 by experienced racing enthusiasts, the company identified a gap in the market for affordable double adjustable shocks, allowing customers to optimize their vehicle's ride quality by independently tuning compression and rebound settings. By focusing solely on these products, Viking keeps prices competitive with single adjustable shocks, offering better performance without unnecessary costs.
Viking conducts all aspects of design, research, and manufacturing in-house, ensuring quick responses to market changes. The company has received prestigious awards like SEMA's Best Engineered Award and has expanded its product line to include various shock types, such as patented race-only Crusader shocks and lightweight aluminum struts. With a commitment to value and quality, Viking aims to provide exceptional products for racing and performance enthusiasts at accessible prices.
| Weight | N/A |
|---|---|
| Dimensions | N/A |
| Fitment | 1973-1987 GM C10/C15 |
| Platform | 1973-1987 GM C10/C15 |
| Manufacturer | UMI Performance, Viking Performance |
| Direct Bolt-On | No |
| Material | Mild Steel |
| Modifications | Cutting, Drilling |
| Finish | Powder Coat |
| UOM | Kit |
| Hardware | Included |
| Color | Black, Red |
| Coilovers | Included, Not Included |
UMI Performance
21 Years In The Industry
North American Raw Materials
Proudly partnering with leading USA steel suppliers, we source the finest North American mined and milled steel
Precision Bent DOM Tubing
Machine-guided DOM tubing bends maintain correct geometry while maintaining material strength.
Laser Cut Plating
We take North-American sourced plating and precision-cut each component with the latest laser-cutting technology.
Durable Powder Coating
Each finished part is properly prepped and coated with high quality Tiger Dry Lac powder coat, providing a tough long-lasting finish.
Consistent Welds
Our highly-skilled welders and robotic-welders provide consistent welds and ultimate part penetration.
100% USA Made
We take pride in providing 100% USA-Manufactured suspension components.
Shipping Guidelines
Flat Rate Shipping ($12.95) is only offered on Retail orders over $149 shipped via Ground in the Continental United States.
All International customers are responsible for any applicable duties and/or taxes incurred on your shipment upon delivery.
Return Information
All returns are subject to the authorization of UMI Performance, Inc. Please email [email protected] for a Returned Merchandise Authorization (RMA) number. Our Sales team will either authorize or deny the request for return at its discretion. Any product returned without an issued RMA number will not be credited. All returns must be made within 30 days of delivery, be in new condition, be in original sealed packaging and include the RMA number on the outside of the packaging. No exceptions. All products and their packaging must be in new and unopened condition. Products that have been altered, installed, or modified are not returnable. All shipping costs for returns are the responsibility of the customer. All returns are subject to a 20% restocking fee as well as the original shipping charges that UMI Performance may have incurred while shipping your order.
Due to the majority of Viking products being drop shipped, we can not offer returns on any Viking products. If you purchase a Viking product be sure it fits your application. If you need technical assistance prior to placing order please contact [email protected]
This '6425 - 1973-1987 GM C10 Rear 4-Link Suspension Kit' fits the following platforms:
1973-1987 GM C10/C15
- 1973 1974 Chevrolet C10 Pickup
- 1975 1986 Chevrolet C10
- 1987 1987 Chevrolet R10
- 1973 1974 GMC C15/C1500 Pickup
- 1979 1986 GMC C1500
- 1975 1978 GMC C15
- 1987 GMC R1500
This 6425 - 1973-1987 GM C10 Rear 4-Link Suspension Kit fits the following vehicles:
1974
Chevrolet C10 Pickup
- 1973 1974 Chevrolet C10 Pickup
GMC C15/C1500 Pickup
- 1973 1974 GMC C15/C1500 Pickup
1986
Chevrolet C10
- 1975 1986 Chevrolet C10
GMC C1500
- 1979 1986 GMC C1500
1987
Chevrolet R10
- 1987 1987 Chevrolet R10
1978
GMC C15
- 1975 1978 GMC C15
GMC
R1500
- 1987 GMC R1500
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