Detroit Speed's front frame is a bolt-in replacement for the original stock subframe. It improves the handling and ride quality by utilizing Detroit Speed's unique suspension geometry. It is the ONLY Chevy II frame in the aftermarket industry with OEM quality stamped crossmembers for improved structural rigidity. The bay bars feature rigid integral hood hinge mounting and are hidden when used with Detroit Speed's Chevy II Inner Fenders package. Spring Rate: 400 lbs/in Spring Free Length: 10 in Double Adjustable Shock: This is the most race winning shock JRi has in its stable. With its two independent adjustments and the enormous range of adjustment it can be set to the exacting demands of the driver and performance levels required while providing excellent ride quality on the street.SBC and LS engines have been designed as a direct bolt-in to this frame. The Detroit Speed frame has been designed, engineered, and developed for the road and track. This frame blends the benefits of current OEM technology and aftermarket performance into one product! The frame is sold in bare metal, uncoated and unassembled. If the powder coat option is purchased, assembly is included.