Does anyone know what this marking indicates?
 

Its on the floorpan just underneath the heater box.
https://cimg6.ibsrv.net/gimg/www.cor...a65b7ea513.jpg

It's a job number written by an assembly line worker.

Does your VIN end with 458 or 958?
:)

I was more curious what the job would have been.

Off the top of my head I dont know.

On my 68 it has 201 A/C written in the same location. The number doesn't match the last three of my VIN. It's difficult to say what the job was on yours without anything else after the number. I know that on my car it was written to let the assembly line know it was to be equipped with A/C.

Early assembly line tracking of what would become your car. For in house use before the VIN was attached, assembly line staff assigned a job number from 1 to 500 and marked the underbody and other parts with the number. For some model years, the VIN has no correlation with the job number. For other model years, you can subtract 500 from the last three digits of the VIN and get the job number. After 72, the job number is often the last three digits of the VIN.

If you look your car over closely, you are likely to find all sorts of chalk or grease pencil scribbles. PB, AT, and UA6 are common (power brakes, automatic transmission, theft alarm).
:thumbs:

Cool deal. Thanks for the knowledge bomb.

I found the number “10” written on the trans tunnel while replacing the carpet in my ‘71 coupe.
Never saw a 2 digit job number

my 68 had the job number in 2 spots that i found..one was at the bulk head by the tank.. the other was inside the engine bay on the pass side foot well...#122, this also matched my tank paper. it was hand written on the paper.

I only found markings in one spot on my '68 coupe. This is on underside of the panel that fits between the rear quarter panels. Over head in the storage area behind the seats.
https://cimg5.ibsrv.net/gimg/www.cor...c108f43302.jpg

Not to high jack this thread (sorry OP) - my '68 has the job numbers in the same 2 locations as 20round mentioned above although there is 5 number difference from the job number shown on the tank sticker. Possible factory worker error??