The front have two different size bolts that go through the leaf springs. 72 and earlier have a smaller bolt. If you are going to use ss or 73 up springs you can use later front bracket. or drill the early brackets. but if you have early springs they are the 1/2 innch holes and you should use the early brackets for the front. I have them all if you don't find what you need. I will be listing them in parts forsale. Steve