Replacing SBP Rotors

According to my manuals that cover 1969 - 1982, the front hub and rotor are a single assembly. Since I have seen two piece units on Mopars, I assume they are after market. The early brakes are 4 piston, fixed caliper Kelsey-Hayes units. Before removing the caliper, push all 4 pistons as far from the rotor as you can possibly get them. Remove the pads. Remove caliper taking care not to damage the transfer tube that connects the two sides of the caliper. Reverse order to re-assemble. Let me know if I can be of further assistance.