Grit dog wrote:
Even though you’ve ditched this thread, I’ll add, offset or backspacing likely has nothing to do with it clearing the calipers. I can’t recall any truck up until the early 2000s that had big enough brakes to not clear 16” rims.
Can't say I blame Sweet Lou, if he in fact did ditch this thread, after you got done with him! So let me get my licks in too...
The 16" rim is actually wider in diameter than a 16.5" rim.
The difference is in the bead taper, which is steeper and more abrupt in a 16" (and all "even" sized truck rims) at 5 degrees, whereas the 16.5" rim has a shallower more gradual bead taper, at 15 degrees.
The steeper bead taper of the 16" rim, combined with the taller bead lip, makes for more secure tire retention, and also makes the outermost diameter (lip edge to lip edge) greater than that of a 16.5" rim.
The drop center contour is also different, and I don't anticipate any issues accommodating what I assume to be drum brakes on the 1972.
That being said, if it were my 1972, and it had original equipment rims, I'd be hard pressed to make the swap, even though I did exactly that in my 1979 E-350 van.
In fact, 3/4 and one ton van wheels from the 80's and up offer another source of 16" rims with the 8x6.5" bolt pattern.
The bump side bodies stick out a bit from the axle track width on that vintage of Ford truck, so as far as visual appearance, a 265 tire will appear to fill the wheel wells... in width, not just height... better than the most fuel efficient 215 tires.