UMI Performance Factory Height High Performance Spring Kits are designed to retain the factory muscle car appearance while adding a crisp ride and modern handling. They are wound from 5160 chrome silicone premium wire with a 530 pound per inch rate in the front and 9254 chrome silicone premium wire with a 130 pound per inch rate in the rear. The linear rate of the springs provide consistent handling characteristics that autocross an pro touring driver's are looking for. The increase in stiffness eliminates the soft floating feeling on the highway and reduces body roll during spirited cornering. The factory ride height is set to be level with the weight of a full dressed small block Chevy or Pontiac, a big block engine with aluminum heads and intake or a modern LS series engine. All UMI Performance Factory Height High Performance Spring Kits are proudly made in the USA and are finished in a tough black powder coat finish.