Hi
I'm going from manual to power steering on my latest project ('70 small block Barracuda)
I have three pumps with unknown history available.
Is there any way to test them out of the car?
Thanks

Off the top of my head the option of driving the suspect power steering pump using the belt double pulley system of a home drill press comes to mind but most likely would involve fabbing up a custom metal plate with mounting holes, plus oil, high pressure valve and hoses.

The pump could be driven on a metal lathe, even using the lathe oil cutting fluid coolant hoses as input/output lines but I would be VERY worried about metal flake contamination.

A “Porta-Power” system could drive the suspect pump as a motor to check for leaks, but this could contaminate the Porta-Power.
A hydraulic log splitter could be used similarly.

You might do a telephone number search in your area for “hydraulic repair” and ask “do you have a test bench?”

I cannot think of a way to test that would not exceed the retail cost of a typical rebuilt auto power steering pump.

Either types are easy to rebuilt with kits out there.
Assuming there isn't any major damage inside.
But would be obvious after taken apart.
Mainly just gaskets.
Hardest part is usually replacing the main shaft bushing.
But it's just a press fit out-in.

If you have a belt driven something, grinder, polisher, small table saw, etc. I'm confident you could mock something up to work using wood brackets. I'm guessing you aren't going into the business of testing pumps! The actual procedure is in the FSM and it's not complicated.