I swapped the Napco 4wd running gear out of a '57 1/2 ton with a rusted out cab & frame to a '59 1/2 ton. If you have all the parts, it's a simple bolt in job. IIRC you have to drill out two holes to a larger size in one of the crossmembers to mount the transfer case. These kits started out as an aftermarket bolt in conversion so they were designed for simple installation. Longer emergency brake cables are needed if you install the 4" riser blocks in the rear which keep the truck sitting level. The correct front brake hoses can be a little hard to find also. The Napco Owners Group is a great place to access a lot of information on these.
