That spacer plate you pointed out can be fitted onto the cam in either of two ways 180° off from each other, so the dimple on the end of the shaft has nothing to do with it. One side of the spacer is dished out for an electric brake shoe wear indicator that was fitted to the '74-mid '77 models. For proper clearance on the brake plate, it must be fitted facing down.
I can tell by looking at your brake plate that it's a later '77 one. As I mentioned, earlier ones had a brake wear switch installed .....
On yours, even though they eliminated the switch, they didn't change the casting. They simply cut off the wiring connector tab and didn't bother to drill and tap the switch hole .....
Your cam, if it's the original, should have the dimple on top. They aren't always easy to see .....
Sometimes it helps if you look down at it from an angle .....
I can tell by looking at your brake plate that it's a later '77 one. As I mentioned, earlier ones had a brake wear switch installed .....
On yours, even though they eliminated the switch, they didn't change the casting. They simply cut off the wiring connector tab and didn't bother to drill and tap the switch hole .....
Your cam, if it's the original, should have the dimple on top. They aren't always easy to see .....
Sometimes it helps if you look down at it from an angle .....