Hi, welcome to the site! I have a 58 Viking 60. (6400). Your Viking 60 is not a 3800, it is probably a 6400 or 6500 (difference in frame length). Choke cable should be the same as a smaller truck (3100, 3600, 3800) as they are pretty much the same cab and doors (grill and fenders wider, hood is also the same). Most cab parts and controls are the same as the smaller trucks. If you are looking on Napa's website, you need to change the vehicle type to medium/heavy duty, then your 6400 will show up.
Mine has an 8x13 bed on it but, it is not a factory bed, the original owner made it (or so I was told by his son)
