For (old) Corvettes and Chevelles I recall books containing the VIN ranges by build month. So based on the VIN you could determine what month the car was built - and based on the range in the month # even approximate the car's build date.

Does such a listing exist for Firebirds, or perhaps for Pontiacs in general? Or perhaps the PHS documentation (that I have virtually no knowedge of) makes this point irrelevant. Just curious...

I'd like to share a story where this information came in handy. About 10 years ago I tagged along with a friend who was inspecting for possible purchase a '70 Chevelle SS LS-6. The owner had this car since 1980, and was very complete and original.

The engine block stamp matched the VIN, and the engine code stamp was that of an LS-6. But Chevy also includes a date stamp on the pad - in MMDD format (0305 = March 5, with no year listed). The problem was that the body tag showed a December '69 build date. No way the engine was built 3 months after the body, right? Well in this case the list of VINs and build dates came in handy. The VIN was a March '70 VIN, which then makes sense with the block stamped date.

It's likely that something either happened to this body and it was pulled off the line (or something), or perhaps there was some lag with LS-6 blocks and they all had this issue. I've never "touched" another LS-6 so I can't say. But either way the VIN build month list "saved the day".

Just FYI I can't remember the exact dates from the story above, so they're approximate - the dates have been changed to protect the innocent ;-)