'73 Dodge van steering wheel play?

Hello all!

I am working on a '73 Dodge Tradesman 300 (B300) one-ton van that has
been converted into a motor home. I have noticed some play in the
steering wheel and I'm wondering if it's normal. It has power steering.
With the engine shut off, it has about 5.5" (or about 38 degrees) of
really loose free play. I have looked at the rag joint (rubber disc
with upper and lower shafts bolted to it) under the hood and it seems
to be OK - I can grab the rag joint and twist it and see the same amount
of movement in both shafts. With the engine running and the van parked,
it gets a little better - maybe 4 to 5 inches (28 to 35 degrees) of
slightly stiffer (than with the engine shut off) free play before the
left front wheel starts to move. I have not driven the van to see how
it performs on the road, as it has a brake problem I still need to fix.

My daily driver is an '01 Toyota, so I am used to fairly tight steering.
Is this much slop just a characteristic of the steering system on the
van, or should I be looking at a rebuilt steering box?

Thanks!

Matt Roberds