Modern radial tires require alignment specifications that differ from the original factory specs developed for bias ply tires. For caster, SPC recommends +3.00° of caster to promote improved return-to-center and more responsive performance. Stock strut rods on the 1st generation Mustangs and FoMoCo vehicles are non-adjustable and often have worn out bushings that can cause excessive movement of the lower rod assembly, resulting in poor handling. A must f or ‘64 -’66 Mustangs on modern rubber, this adjustable caster rod features high durometer OE-style bushings to protect the chassis mount from damage and has easy caster adjustment. It will provide the positive caster needed for improved tracking and modern geometry. If adjustable camber is desir ed, look to the SPC complete control arm kit # 94218.