[mr48chev]

First, does the "early" big block power steering pump you have match up to the engine and long water pump?

The basic pump was the same for years but the differences are in the reservoir and the outlet valve on the high pressure side. Reservoirs are model specific and often don't fit different engines or even different models with the same engine.

Set the pumps side by side on the bench and take a look at the dffferences and similarities. You should see that the outlet valves (fittings) are in the same spot on both pumps and the location of the bolts that hold the reservoir should be in the same spots.

You might get away with swapping the reservoirs from pump to pump. It is an easy job and you mainly have to make sure that the O rings are all in the right spots when you put it back together.

You may have to mix and match pressure hoses to make things work and you may have to swap out the pressure outlet valves (fittings) from pump to pump so that the hose will connect to the pump.