It's obviously fabricated and has the appearance of a diverter valve, maybe industrial. If it is in fact a pump, it sure doesn't look automotive. Why do you think it's a pump and how is it be driven?
That pump is for a V8-60 Midget : a socket that fits that nut is welded to the crankshaft bolt & the center tube faces down for the lower hose from the radiator. The two other tubes go to either side of the block to feed water into the lower part of the "60" block. These were often fabricated by the car owners, although this one looked like a "store-bought" unit. I had a similar unit on my "flattie" sprint car years ago. Almost missed: those 2 tabs are to bolt the pump to the pan bolts on the engine to secure & locate it.