I replied to your other topic posted but now that I look at your engine and compressor I realize what you are dealing with. I'd say you need to find an assembly manual for a 66. Just guessing I'd say the cast iron one goes on the bottom front pivot and bolts to your water pump (flipped opposite from the picture) since it has an offset mount like the water pump. The stamped steel one goes on top to the belt adjuster slot, most likely on top of the cast iron lower mount to the water pump- I just can't figure out why it has the 2nd offset bend with the hole- perhaps other brackets missing? Also looks like there should be another back pivot bracket(s) for the compressor that mounts to the #2 exhaust port bolts.