PS Pump for 273 small block, what will fit?

I believe the 72 360 pump has brackets that are designed to work with the aluminum water pump. Check to make sure. The TRW Thompson pump used on 67 and 68 come rebuilt with the pulley on it. The Federal pump which they started using in I believe 69 does not come with a pulley, you have to reuse your old one or find a donor pump to use as a core. From your pictures it looks like there is another pump out there for the early cars. The units I found online are the TRW ones which do not have the same mounting points as your original, but with the right brackets is probably the closest match for your setup without major changes.