Purpose of this thread is to focus on the change from the early square corner sill plate design to the rounded outer corner versions used later in 65 production and through many of the following years. We've had earlier discussion but those were not well focused. Of course these were often replaced over time or when the car was restored and since the service replacements were made in the new style this can add to the challenge of determining when the change took place and I use the square style (since those are rarely added to a rounded corner sill plate car) as a guide and carries more weight in the interpretation.
In surveying the data I had I have the following at this point
Highest coupe and fastback VIN with square corner sill plates. - 5F60364x
Highest convertible VIN with square corner sill plates. - 5F63103x
Lowest coupe and fastback VIN with rounded corner sill plate. - 5F38xxx
Others found in the general range - 5F6286xx - 5F6287xx
Currently have no convertibles with rounded corners in this production period
Dark purple bar represents the transition period for coupe and fastbacks currently based on data available while the dark and lighter purple represents the convertible transition period currently
Examples
The first/early design
For coupe and fastback
For convertible
++++++++++++++++++++++++++++++++++++++++++++++
Later
Coupe/fastback
Convertible
As always, we invite other reports and findings. Please keep to the plant and year
