* Will not fit vehicles manufactured before 3-1-1999 with 5/8" track bar bolt head size.* Vehicles equipped with 2 piece rear driveshafts may require the carrier bearing KIT ZONF5401.* If vehicle is equipped with rear top mounted overload springs 4 of u-bolt part number ZONU4035 may be required.* Trucks equipped with gas engine may achieve a slightly higher front stance.* If truck is equipped with curved/radiussed style front ubolts order kit # F1. If truck is equipped with square style front ubolts order kit # F2.* Dually vehicles will require quantity 4 u-bolts ZONU4062 (12.5" long) or ZONU4063(14.5" long)