Early Disc Brake ?

Picked up a 66 Valiant SW this weekend and put it on stands to check the front brakes. Surprise, it's got disc! Anyway, my question is about the brake drag on he rotors. It seems to be excessive on both sides. What would be "normal" resistance when rotating a wheel? Should it be the same as drum brakes are? What could cause both wheels to drag so much? Without the wheels on, it takes some force to spin the rotors by hand. Any advise would be appreciated.