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The UMI 6425 kit replaces the outdated leaf spring setup on your C10 with a race-inspired 4-link rear suspension system featuring unequal length trailing arms, an adjustable panhard bar, and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 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.
