These heavy duty cam bolts replace the upper control arm mounting bolts. This kit has the added convenience of slip-on cams which makes installation easier. Remove the O.E. bolts and replace them with these cams, rotating to provide camber and caster adjustment. Use 74910 punch to remove the O.E. slugs and elongate the holes. If necessary, 87400 includes 4 cam and bolt assemblies to cover both sides of the vehicle. California Residents WARNING