Here are a few pics of the brackets, I picked them up from a wrecking yard off am 81 f250. The cast bracket that bolts to the head has a part number you can see in the photo, the stamped part does not have anything on it.
Hope this helps you out, I had to alter my AC plans as my truck is really vapor locking in the heat. Always something with these old rigs...
Chuck
1981 flareside 4x4, C6, 351M