I don't know if there is an actual account from someone managing the plant on how they "spun" the numbers with sequencing. I have a theory, based on what I know in today's production assembly process.
Prototype - clay or fiberglass models from which sections and dimensions are correct to design.
Engineering drawings made for tool and die shops
verification model- first stamped steel panels, assembled to a body fixture, verified in grid, usually JOB 1.
This verification model is the one from which all others will be measured to, within agreed upon tolerances.
If the car didn't build correctly, changes may have been made, moving to for example to JOB2. These changes are reflected by "CNs". Running changes made by engineering after tooling release dates.
Subsequent jobs are listed as Vehicle Development.
Some of these departments had numeric codes.
Electrical
Brakes
HVAC
Powertrain
Transmission
Suspension
Crash Lab
photography/press
Cars built for these departments may have carried a code found in the VIN, thus enabling the plant manager the ability to track the car built for a particular department.
As stamped panels cone in the plant, they go on racks.
A car starts life on a jig with people, now machines, welding pieces on to a fixture.
As it moves forward on the production line, the more complete it becomes, the more specialized job it is for the oprator- TRACKING OPTIONS
here's where a little theory I have comes in about your non-sequencial VINs and non sequencial sequence number comes into play.
There is a central processing facility that had the orders, with the options. That the customer wanted.
Let's say cars 1-4 had been built with an AC firewall, and only 1,2,and 4 were supposed to be cars with the AC firewall.
The plant manager would go through the processing sheets and fin the next one with the AC option, and grab that Tag.
The same could be said if the plant ran out of supplies. Engines, sway bars, whatever.
I think my theory only works if the plant didn't stamp the VINs until the bodies were assembled.
I think the orders came In from the processing facililty, and the orders were processed
before unordered cars. (Again, a guess)
Sequencing is still very much a part of how we build cars today.
At the New plant in Toronto, they have Challengers, Chargers, and 300s rolling down the line. Are those numbers are all sequencial by VIN? ( good question, - I don't know)
The plant uses sequence codes to help allign the parts with each model.
I am sure it was not perfectly sequencial back in the day, but it has been refined a great deal as we move forward, making it nearly error proof. Of course technology helps out quite a bit too.
Could I be wrong- you betcha!
Could some aspect of my theory be correct?
It's plausible.
Dan
