Chrome Hash Marks Placement
Richard asked when the change from screw on type rear chrome hash marks and the smooth chrome C-Pillar molding was made. According the the VTCI Official Factory Specifications (OFS) (don't have one? Get one!) the factory made the switch from screw on type rear chrome hash marks to speed nut fastened hash marks in mid-December 1959, early in the production run. The same thing applies to the smooth chrome C-Pillar molding to the ribbed version.
I also noticed that they changed from a single screw on the headlight door at the top with a V clip at the bottom to a two screw arrangement, top and bottom later in the production run. The OFS did not say when they made the switch, except to say that early 1960 production cars had the one screw/V clip arrangement.
Here are a couple of pix from the OFS.