This is a great way to upgrade from original leaf spring suspension. Unlike our competitors, Detroit Speed's exclusive new 4-link geometry design is uncompromised to achieve the best possible handling. The new Detroit Speed Swivel-Link™ (Patent No. 7,398,984) allows the suspension to fully articulate with smooth solid motion an no binding. The best feature is that this is achieved without heim-joints. Heim-joints are noisy and prone to short-term life. The Detroit Speed QUADRALink utilizes tuned high-durometer rubber bushings (in place of heim joints or squeaky urethane bushings). The long upper links provide great pinion and u-joint angle control. Contrary to competitors' kits, our kit utilizes a panhard rod that provides precise and effective rear axle lateral location during hard cornering. The panhard rod is adjustable as ride height changes for roll center control. The rear upper shock crossmember strengthens the rear body and frame section. Don't settle for anything less than Detroit Speed's QUADRALink rear suspension! Spring Rate: 175lbs/in Spring Free Length: 11in Requires Narrow Fuel Tank: PN: 080184DS - Holley Pump Required PN: 080145DS - 1000 Series Fuel Pump PN: 080119DS - Carbureted PN: 080175DS - LT1/LT4 Fuel Pump