Made out of 1-5/8x.134" wall mild steel tubing. These mandrel bent frame rails are lighter and more compact than the 2x3" box rails. This is an advantage in cars where space it at a minimum. Our dropped crossmember has more drop and tighter bends making it easy to assemble the frame with an outside width as narrow as 20". The 4-link is mounted under the frame rails, not on the inside like our competitors. This makes the suspension as wide as possible even with a narrow frame rail width, creating a better handling vehicle. The raised rails over the rear axle allow for lower ride height than rails design to go under the stock floor pans. Designed for our battle cruiser style 4-link (part nos. 6205 and 6248) and coil spring or coil-over shocks. Kit includes a pair of frame rails; dropped front crossmember; upper shock mount crossmember; upper shock mount tabs; rear crossmember; 54" long subframe connectors; hardware; instructions and drawing. Shipped unassembled by UPS. Options include aluminum or steel rear floors kit to match our frame rails; 1-5/8" round dropped crossmember and subframe connectors; or 2x3 box front crossmember and subframe connectors; and factory welding.