[lolife99]

Your concern should be what year ball joints and outer tie rods your kit uses.
That’s a must know item when buying spindles. They have to match.
1-1/4” rotors were used in 71-72 trucks.
Most every conversion kit uses 1-1/4” rotors.
Some 73-87 trucks used 1-1/4” rotors.
Some 81-87 trucks used the light duty 1” rotors.