Chad, that tight date gap is perfectly possible on high volume engine codes out of the Pontiac MI assembly plant. I've been able to document it many times. The home Pontiac Assembly plant also had a Body Bank, where painted body shells were slotted awaiting their turn to make it on to the line. Other assembly plants, like Fremont, were assembling several divisions A body's, and did not have a Body Bank.
The most accurate way to determine when a vehicle was built is to find an original build sheet and look at the scheduling date. This scheduling date is typically correct, though the date on the sheet was inputted at least 4-5 days earlier anticipating certain assembly plant loads. Have been able to document this on early '71's that were "stuck" due the strike. Unfortunately, PHS's invoice copy does not have the scheduling date, only the shipping date, still a valuable piece of documentation.
I am glad you mentioned the Body Bank as I have been attempting to gather some more info on that subject. Perhaps you can help me with some questions...
What is your understanding on where the body bank was used? The CRG website says the body bank (when used) was located between the Fisher and Final assembly plants. Trimmed out bodies from Fisher were stored in the body bank to await sequencing. This info is specific to Chevrolet F bodies but the info should relate to GM assembly in general . Here is the webpage:
CRG Research Report - Camaro Assembly Process
However, I have spoken with a former worker from a Los Angeles area assembly plant who says their body bank was located on the Fisher Body plant between the body and paint shops. All the bodies in the bank were 'body in white' cars (BIW). (finished cars, primed and ready for paint) Do you think it's possible that many plants had a 'body bank' but some were a bank of trimmed out cars while others were BIW cars? I would love to see a photo of the body bank....that might tell the story. I've heard the Pontiac Michigan Assembly plant had a 8 lane body bank. When I compare Invoice Date found on the BHC to the week code on the cowl tag, the invoice date usually is sometime during the next week following the cowl date. It can be a little longer for cars assembled at the Pontiac plant, it's not uncommon to see a 2 week spread between those milestones, I wonder if the size of the body bank at the Pontiac plant has any effect on the date spread? Although, I've really only seen a couple dozen examples so it would be helpful to see some more data to build a better picture of what actually happened.
Based on the info I've been able to gather so far....it seems the Invoice Date on the BHC best represents the actual build date. This should be the date the vehicle was cleared and released for delivery. Generally speaking, I believe the production sequence is summarized as follows:
- Order sent to Fisher Body where cowl tag is coded and week date stamped
- Body panels welded together, doors and decklid hung
- body shop prepares body for primer and paint
- "body bank"???
- Paint shop (still at Fisher Body plant)
- Fisher Body Trim shop (upholstery, glass, etc)
- Painted and trimmed body delivered from Fisher Body to Final Assembly plant (usually next door)
- Body sequenced for Final Assembly (VIN assignment, Broadcast Sheet printed)
- Final Assembly begins (VIN attached to body)
- A/C-heater box installed, instrument cluster, forward seats carpet
- Body married to rolling chassis
- front clip, hoods and bumpers installed
- Test, QC Inspection, Invoice, ship
Does this sound about right? Sounds like the Fisher Body work lasted about 2-3 days, the sequencing stage might be a day or two and then another day for final assembly. Barring any delays...maybe 5-6 days from start to finish?