[lolife99]

Your truck has 1.25" rotors.
Buy 71-72 drop spindles for a direct fit.
Early Classic, Belltech, McGaughy's, Western Chassis, are all good brands.

73-87 spindles will require a different upper ball joint and outer tie rod.
This is what was neccessary 30 years ago when 71-72 specific drop spindles weren't produced yet.

CPP still stock, promotes and sells this 73-87 conversion kit.
Why people buy this kit is beyond me.