Rubbing sound?

The pads are supposed to be fitted. Here's the relevant pages from the 74 shop manual:

http://www.forabodiesonly.com/mopar/showpost.php?p=1970159077&postcount=7

Look at the 3rd photo from the bottom. The pads can rattle and move around otherwise.

Also check carefully that a wheel / wheel weight is not rubbing on something, the tops of the calipers, the A arms, the grease fitting or even the brake hose.