[78Macho]

Need some guidance please.

In researching the correct/valid date code Super T10 for my 1979 project led me to the question of how the VINs were assigned to one car line coming out of two different plants. I understand Norwood cars VIN had the N designation and Van Nuys cars had the L designation. Did the plants communicate between themselves and when a build started the next consecutive number was used with the corresponding plant code or did each plant start at 1 and work up from there. So then, there could have been a car VIN 25110 from each plant with the L or N differentiating them?

So, assuming both plants got their Super T10 from same supplier, would the date codes have been the same or close if I were looking at codes from Van Nuys versus the Norwood plant where my car was built?

[Keith Seymore]

Your second scenario is correct.

Both plants assign sequential numbers incrementing up one by one, with no connection one plant versus another.

The uniqueness in the VIN comes from the plant designation.

For example: in my records I have 65 GTO's with VINs 237375P115814 (Pontiac, Michigan) and 237375Z115814 (Fremont CA).

Relative to date stamps: no idea. Since they are incrementing up independently it is a function of line rate, number of production shifts, and any unintended work stoppage relative to maintenance breakdowns, material shortages or local union activities (ie, strikes). You'd have to check dates of comparable builds to get an idea of how the two plants were ramping up compared to one another.

K

[78Macho]

Keith-

Thank you very much for your reply and explanation! It makes sense.

I previously owned '79 L 49346 buildsheet date (upper left corner) of 01/30 and currently own N 43830 trim tag date of 02A (no buildsheet available) which is first week of February.

So, comparing the two plants, Van Nuys was ahead of the Norwood plant.

Another question Keith? How do the buildsheet dates relate to the PHS dates and to the trim tag dates?

Jim

[Keith Seymore]

Originally Posted by 78Macho

Another question Keith? How do the buildsheet dates relate to the PHS dates and to the trim tag dates?

Jim

They relate to one another but are not locked solidly together.

a) Buildsheet date - comes first. There are specific build sheets for each part of the build (ie, chassis line, motor line, body trim, final line) so it depends a little on which sheet you are happened to find. Build sheets are generated and distributed ahead of the actual build, by definition, because that's what the operator is going to refer to in order to know which part to put on.

b) Cowl trim tag date comes next and will normally precede the completion of the build by days or weeks. Could be longer than that, but that would be super extenuating and would require the body to be built and stored (without completing the vehicle), either in the paint or trim body bank, or the aisle. This can happen when the body is started but it is determined after the fact that significant chassis or powertrain parts were not available or because the chassis was started and damaged in process and had to be started over. I didn't say this explicitly but the body is started well ahead of when the chassis is started.

c) PHS dates are invoice dates, and come last (because you have to have a completed vehicle in order to sell it). They can vary based on how long the vehicle sits around. There can also be multiple invoices for GM owned vehicle, and an invoice can be generated if the vehicle changes hands within GM, and then again when sold to the final end customer or dealership.

This order has to be preserved but the time window can vary wildly depending on assembly location and what's going on in the world. My car (build in Pontiac) has an 09A trim tag, was completed on 9/18, and invoiced on 9/21. On the other end of the spectrum there are cars that were built and sit around for months, either because nobody wanted them at the time or because of a strike.

It's a little bit like telling how fast you are going by looking at the gas guage instead of the speedo. There's a relationship... but it's fuzzy.

K