You can use the original steering column.
many of the parts vendors, like Chevy duty, sell a bearing to install in the bottom of your old column after you remove the old box.
I did, and have pictures on the link below.
I used an IH Scout PS box, but I also swapped my front axle.
If nothing else, my pictures may give you some ideas.
Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-