Yes the older 8 lugs where 16" and used the cool larger dog dishes lol.I think back then that the 8 lug trucks used 16" wheels, and those have the larger size dog dish hubcaps. Unfortunately I don't have any actual trucks around of that vintage to look at or get measurements from. Other members do though....
Fords also used 16" 8lug that used the large cap. I have ford e-250/350 wheels with squarebody era caps ran the bowtie ones till i found the gmc ones
And i know ford parts on a chevy but for FREE how could i say no