UPR Products Extreme Lower Torque Box kit for 79-04 Mustangs replaces the entire factory lower torque box assembly. The factory torque boxes are notorious for tearing and pulling away from the body as they are spot welded in and that happens with stock power levels. These Extreme Torque Boxes are a perfect replacement for your damaged torque boxes or highly modified race car reinforcing the floor and lower suspension mounting points. They allow for instant center changes and easy access to the control arm bolts for changes at the track. Control arm mounting points are made from 1/4" thick steel. Includes stainless steel pins to convert your Pro Series lower control arms (single or double adjustable) that are staggered so they can be mounted in the center or offset left or right by .250".