Our exclusive Detroit Speed 1968-87 GM C10 Speed Kits are designed to work as an integrated system on your truck. By utilizing our proven Detroit Speed components and carefully selecting components designed to complement each other, each speed kit is for your driving needs with the ease of a bolt-on package. Speed Kit 1 is designed to bring your classic GM truck into the 21st century with improvements in ride and handling. Speed Kit 2 takes performance to the next level with a sway bar that is 127% stiffer than the factory sway bar. Speed Kit 3 is the most advanced handling system you can buy for your GM truck. It gives you the ultimate steering performance of today's modern trucks. Spring Rate: 950lbs/in, Spring Free Length: 11.1-inches.