Need Help: Power Steering Transplant (307)

[ChevEE]

So I recently purchased a 70 C10 with a 307. It did not originally have power steering. The previous owner had begun adding power steering (transplant from unknown application) and completed everything except for installing the pump and crank pulley. He had the pump and brackets though, which he gave me with the truck.

So I got around to attempting the install today and can't quite figure out the puzzle. I'm not sure what he pulled the pump and brackets off of and I can't see how/where it mounts in. Here are some pictures that I thought might be helpful. Any help would be greatly appreciated. I have spent a lot of time going through pictures of these engines online and these forums and have not see any similar brackets yet.

In the pictures there are two brackets. The larger one is actually a duplicate of the one already installed on the pump.