1973 Scamp Brake Question

Most slant 6 and 318 A-bodies had the 7 1/4" rear and came with 9" front and rear.

Up until 1972, yes. In 73 and 74, the base brakes were 10" front, 9" rear drums (I'm not sure about 75-76). 1972 was the last year they put 9" drums on the front.