The inside diameter of my 67-72 caps is approximately 11 5/8". 60-66 1/2 tons did use clip-style caps on 15" rims. See
http://67-72chevytrucks.com/vboard/s...d.php?t=702839
You could retrofit the clip-style caps on these 16" rims if you did something like post #50 on the above link or something like this:
http://www.laroke.com/larryk4674/smo...er/hubcaps.htm