I'd suggest waiting to make the power steering modification until you see how the truck steers with a well-restored standard steering system. Particularly with a relatively narrow tread contact patch you might decide P/S is not necessary or desirable. The steering effort increases pretty dramatically as the tires get smaller and wider, and it looks like you're going the other way.

Adapting power steering to a straight axle setup can be time consuming and expensive, particularly if you plan to run the original stovebolt six engine. Electric-assist steering is probably the easiest and least expensive way to go if you decide you really need power assist.
Jerry

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