It's an UCA relocation mount from Baseline Suspensions. It raises the rear upper control arm mount to adjust instant center and anti-squat. Also has track locator built in which Centers the rear housing. Fox body fords and Gbody GM cars have triangulated 4-link suspension. Once we replace all the bushings with spherical rod ends there is nothing to stop the housing from moving side to side during launch or cornering. You see the foxbody twist or Gbody shuffle .... It's poor control of the suspension. My car also has an ARB but it's not necessary with a good locating device unless really going after it hard...I plan on that. S197 cars have an panhard bar or sometimes called a track bar in circle track. That is what controls the housing sway in those cars.