Sorry, just checked back here (forgot you don't automatically get emails from this forum).
I'll do some measuring/checking on my '63 in the next couple days and post back; it's really odd your 16" wheels won't go on. My wheels are Accuride 28177's (IIRC), FWIW.
The site will contact you if you go to the top were it says topic options and click on it and then click on watch topic and set it up to send automatic emails when topic is replied to.
I will have to check and see if my wheels have an Accuride # on them. I know my latest wheel(2000+) has the widest inside diameter of any of the other wheels I have tried and still did not work. All the wheels I have work on the back of my 70 1 ton even though it has the same brake diameter because the hub mount face protrudes about 4.5" from the face of the brake drum so it sets the wheel far enough out to allow the use of the 16's. My 61-64 hub mount face is only set out about 2" from the drum so the wheels contact the drum edge before seating. I am going to look for the factory 17's at the swap meets the next few weekends and hopefully find one to measure. I may end up parting the 70 1 Ton and if I do, I will probably pull the 70 rear for possible future installation in one of the 61/64 because, by the book, they have 5.14 gears in them and the 70's glove box shows it to have 4.10 gears and no-slip differential. This will allow the use of the 16" wheels and also have a much better driver gear ratio.
