ReadyLIFT introduces the 69-39400 4" SST Lift Kit for 2019-2023 Chevy Silverado and GMC Sierra 1500, compatible with Adaptive Ride Control Suspension (ARC). This kit, replacing the 69-3940, is designed for both ARC and non-ARC trucks, offering a balance between a lifted stance and factory ride quality. The 4.0" SST lift kit includes a 4" front lift and a 3" rear lift block. The front lift uses heavy-duty, laser-cut fabricated steel top mount strut extensions with an offset for improved strut and wiper seal angles, plus a CNC-machined billet Aluminum pre-load spacer, enhancing driveline orientation. It accommodates up to 295/65-20 tires on 2019-2022 Chevy with XD Series Demodog 20x9 0 offset wheels (35x11.50 max), while the 2019-2023 GMC Sierra and 2023 Chevy fit up to a 295/55-20 tire due to fender flare constraints. The kit features new tubular steel upper control arms with optimized ball joint pivot angles and maintenance-free TCT pivot bushings, ensuring proper suspension geometry. The rear lift includes 3" tall OE-style cast iron rear lift blocks with axle pad locating ears and longer U-bolts, offering a subtle rake that complements GM's body lines and supports towing and payload. However, this kit is not compatible with Trail Boss, ZR2, AT4, or AT4X models, nor with vehicles having rear composite mono-leaf springs, identifiable by round U-bolts. It only works with traditional steel leaf springs, marked by square U-bolts. Tire sizes compatible are 20x9 0 offset 295/65 R20 for 2019-2022 Chevy and 295/55-R20 for 2019-2023 GMC & 2023 Chevy. The use of Auto 4 Hi feature is discouraged, and the kit is not suited for 2019 Limited OLD Body Style vehicles.