Problem with rear drum brakes

If you get a hardware kit, I suggest one w/ the newer style self-adjusters (say 1971+ Dart). There are 9 & 10" drum systems. Looks like yours is 9". 10" has a triangle washer at the top to help secure the shoe ends. The 9" doesn't. I first thought those washers were missing in my 64 Valiant (based on 65 Dart w/ 10"), then found they were correct for 9". As said, swap your shoes on both sides (short lining to front). The washer on your L side is incorrect, but probably doesn't hurt if it fits. But keep it simple. Any parts that come lose can jam between shoe and drum, which happened in my 69 Dart when a self-adjuster cable broke.