Power steering pump bracket id and questions

[Rust-O-Matic]

Can anybody help me identify the Frankenstein'd power steering pump setup in my 66? The truck has the factory gear box and ram style power assist. The engine is a late 70s 305 out of who knows what. The pump appears to be late 70s style as well. The bracket currently on it doesn't appear to be correct for this application because the slotted mounting hole (on the bracket attached to the front of the pump) is slotted in the wrong direction and doesn't allow for adjustment.

I've attached some lo-fi pics. Sorry about the craptastic quality. The first one is of my filthy engine before I started painting everything. It kinda shows how the pump was mounted. The next two show the front and back of the pump once it was removed. The next shows the repainted rear bracket mounted to the engine. I also included one more pic I swiped off of here, showing a proper 78 c10 bracket setup.

After searching quite a bit one here and Google, none of the 70s style brackets I've seen look quite like mine. The rear bracket is different, and the front one has different mounting holes (the slotted one is on the opposite side, and is slotted vertically rather than horizontally like mine).

So, my questions are:
Does anybody know what I have?
Should I swap the front bracket for one that is slotted the other direction so it's adjustable?
Is this pump even suitable for use with the old ram setup?
Are all late 70s pumps basically the same? (I'm kinda concerned my hoses won't fit the replacement pump)
Oh, and the pulley seems huge, about 6 1/2" diameter. Does this matter, or should I just roll with it?