Hans-
I updated the worn out manual box on my '67 with power steering box. Available from Advance Auto Parts for around $85. It is a bolt in swap and WELL worth the money! A rebuilt pump will run you about the same $. I had several pumps laying around so I did not have that expense - regardless it is still worth the money and makes the truck MUCH easier to drive.

'67 Chevy C-10 283/350