A little more information on what mod's you have already made to your truck - ie. what engine you have installed - is the truck totally stock now ?, etc. would be helpful.
You might try a search of the Forum - I'm sure I have seen some posts over the years concerning power steering mods to straight axles. I have a mid-seventies tilt column installed in my '40. You can use the same hanger location under the dash ( with a new bracket ). As Leonard said, need to support the bottom of the column, then a matter of routing the shaft with borgeson joints and bearings to connect to whatever box you end up with. Lots of brackets available for small block chevies - not sure about the various sixes. Maybe try " Bills Hotrod Accessories " - they have a multitude of applications.

1940 Chevy KC 1/2-Ton
In the Stovebolt Gallery