Some years back I remember reading an article in one of the automotive trade magazines. Motor Age comes to mind. In the article it was mentioned that someone made an electric P/S set-up for a 50's Buick. It was actually attached to the steering shaft in the column under the dash, almost at the firewall & some what to the right.
The installer was so surprised at how well it worked.
Sorry I can't be any more helpful.
Do a goggle search on electric P/S conversions you may find it.
Tom T.