I have this box installed in my 56 Ford F100 truck. I've been trying to find out what this box came out of. The box has an S on the side, which I'm told is a Saginaw box. I've also been told this might be from an econoline van? Anyone seen a box like this or know what it might be?

 

Its not from 61-67 Econolines. They have a steering shaft that is also the worm gear in the box. No breakaway rubber. Maybe a newer econoline from 68-75.
Also the early Econolines the steering arm goes out the side of the box to a pitman arm that then goes down to the trailing arms and the tie rod for the left wheel.