The inside/outside measurement for the hubcaps I run on my truck. Another old truck guy was asking about them, so here they are.
The hubcaps in these pictures were originally for a base model Chevrolet Nova 1971-1973ish. Part number for the hubcap: 39961381
04/09/2005 : details, photos of the caps on the wheels, parts numbers
(show the caps mounted on the wheels)