3624 - 1991-1996 Impala SS Adj Ext Length Upper Control Arms - Roto-JointsFor ease of adjustment UMI has designed our upper control arms with on car adjustability. Pinion angle adjustments can easily be made in the garage or at the track and making adjustments is as simple as loosening two jam nuts. Using UMIs chrome moly on car adjuster, simply turn the adjuster with the control arms attached to the vehicle to quickly lengthen or shorten the control arm. As the control arms are shortened or lengthen the rotate the rear end