Difficult to answer , there are different brake pkgs ,
70 R/T could have 10.5 disc or 11" x 3" drum in front , it used a unique proportioning valve 70 only , should have 10" x 2" drum on the rear
72-74 Should be disc only on the front but the caliper , spindle & brg size is different & 10 X 2" drum rear
