Fabtech K1220M 6-Inch Lift Kit with Front Extensions & Rear Stealth Shocks — 2025 Silverado 1500 4WD

Fabtech K1220M retains the factory front coilovers using lower shock extensions and supplies replacement spindles, crossmembers, rear blocks and two rear Stealth monotube shocks.

Application

• 2025 Chevrolet Silverado 1500 Custom, LT, WT, LTZ, High Country or RST; V8 gasoline, 4WD, crew cab with short bed, and stock suspension. Verify exact year, trim, drivetrain, cab, bed and installed equipment before ordering.
• For steel rear leaf springs with the correct matching round U-bolt configuration only. Does not fit composite rear leaf springs, Adaptive/Magnetic Ride Control, Super Cruise, AT4, Trail Boss, 2WD or other cab/bed configurations. Denali and 2026 models are outside this listing.
• Nominal 6-inch system. The supplied rear blocks are physically 5 inches tall; this is not a claim of 5 inches of added rear ride height. Factory wheels and tires cannot be used.
• This listing is for Chevrolet Silverado 1500 applications only; GMC applications are outside this listing.

Package contents

• One FTS21250 component box 1: front and rear crossmembers, driver and passenger differential brackets, sway-bar frame brackets, differential skid plate and specified installation hardware.
• One FTS21308 component box 2 for 2025: driver and passenger replacement spindles, two FTBK5 5-inch rear blocks, four FT769U round U-bolts, two FT20664 axle spacers and specified tie-rod ends, rear bumpstop spacers, rear brake-line brackets and subassembly.
• One FTS21252 front shock-extension kit: four FT20568BK brackets, two FT20847 extensions, two FT20891 shock-to-arm mounts, two FT20872 bottom plates and the specified bushings, sleeves and hardware. Factory front coilovers are retained; no new front dampers are supplied.
• Two FTS6240 rear Stealth monotube shocks. Two new dampers total, both rear.

Installation and requirements

• Professional installation required. Read the current FT21250i instructions and inspect the complete kit, factory suspension and alignment before work.
• Remove and reposition the front differential and replace the crossmembers. The driver-side rear crossmember/control-arm mount requires a 2-inch cut; the driver differential bracket requires a 1/2-inch drilled hole. Follow the exact mounting and torque instructions.
• The front extension branch requires pressing out the factory lower coilover cross-shafts and bushings, fitting the specified aluminum half-bushings and brackets, and rotating the strut bodies 90 degrees into the new lower mounts. Follow the FTS21252 procedure; do not use the separate Trail Boss/AT4 extension parts.
• Install the replacement spindles, axle spacers, tie-rod ends and supplied brackets. Trim 3/8 inch from the factory threaded tie-rod ends and cut the brake-line bracket tabs as instructed. Relocate and secure the brake and ABS lines.
• Install the rear blocks with the correct round U-bolts, bumpstop spacers, rear brake-line brackets and the selected rear shocks. Verify all tire and line clearances through suspension and steering travel.
• Align to factory specifications, adjust headlights, and recheck fasteners and wheel hardware after 50 miles and periodically.

Tire and wheel guidance

• Manufacturer guidance, all with minor trimming and 5-inch wheel backspacing: 35/12.50R18 or 295/70R18 on 18×9 wheels; 35/12.50R20 or 295/65R20 on 20×9 wheels. Verify actual clearance on the vehicle. Wheels and tires are sold separately.

Manufacturer part number: K1220M. Manufacturer product details.

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