Our 1973-87 Chevy truck rear 4-link kit uses a 220lb. spring and a 5" stroke shock for a smoother ride. Longer 4 link bars offer a smoother weight transfer, which trucks desperately need. "Parallel" 4-bars do not offer any weight transfer. Kit comes with a 30" rear mounted panhard rod, that has less radial deflection and lower roll center than short, top mounted locators. If you're building a hot rod truck, build it with parts designed for trucks. Like this 4-Bar kit. Designed to use a 5-stroke coil-over, the only kit on the market that will give you the ride and performance you're looking for.