327/307

[william]

In my many decades of studying Chevrolet documentation, I have come to take any 'date' with a grain of salt. A good example is the famous chambered exhaust recall. The 1st notice states:

"Consequently, and effective in production on November 25, 1968..."

The letter to owners for the second recall stated:

"...produced prior to December 4, 1968..."

Another example comes from the 'last car of the month' report. I have seen an NCRS doc listing a VIN 12 units later than the report.

I have spent much time reverse-engineering both NOR and Van Nuys production calendars. It will always remain a work in process but the current version has N570099 final assembly occurring on January 2, 1969. Taking Chevy data at face value, it was the 112th car off the line that day and was in process during calendar year 1968.

I have stated many times the date on the body tag is at best only a general indicator of when a car was final assembled.

[dldebertin]

trim tag jpg attached

[dldebertin]

I could believe that the car was mostly complete with a 327 engine already installed and the 12D trim tag in place by Dec 31, 1968, but that the car did not actually roll out of the plant until Jan 2nd 1969. That would be consistent with the idea that no Camaro had a 327 installed after the Dec 31, but not everything that had a 327 installed had rolled off the assembly line to be shipped to a dealer on Dec 31 or earlier.

[bcmiller]

OK folks not quite sure this seems to be such a big deal.

It seems that if cars were in the system for the build to start 12/31/68 or earlier, they got the 327.

If they entered the system 1/1/69 then they got the 307.

ALSO, if people actually read the information that goes with the VIN and production table
http://www.camaros.org/geninfo.shtml#HowMany

you will find this.

The list below is Chevrolet's documentation of the end-of-month VIN for the GM assembly plants. * Due to several limitations the VINs in this list will not necessarily correlate exactly with either a specific calendar day or the build week on the cowl tag. The data for some months (especially May and June 68 at Norwood) deviate significantly from actual build dates, while other months correlate well.* We are unsure of the source of these deviations, but uncertainties include:

It isn't known what day of the month was used for logging the monthly production, or if the same system was used for all years.
Vehicles were NOT assembled in the exact order of VIN. For any given VIN selected as the nominal "last" for that month, it is likely that slightly lower or higher VINs might either still be in process, or might have already been assembled.
The build date on the cowl tag is when the body was started. It was attached 3-4 days before final assembly of the car was completed and build week dates did not always align with calendar weeks.
Despite these limitations, the list remains a useful guide for approximate confirmation of date as to when a given VIN was built.

[KurtS]

BTW Richard, I wouldn't count on those end-of-month records to quite that level of accuracy.....

Yup, people still quote the monthly reports and never read all the caveats. I don't know how to make them clearer. Any suggestions?

9N571395 is the last known 327 car. 9N571561 is the first known 307 car. Pretty clear transition. Except there is one reputed 327 car built about 2 days later. I never saw the engine pad for it - maybe the POP was in error on that car or it was just scheduled late.

[dldebertin]

?  Typo?

[KurtS]

Yup, got distracted in the middle of writing it. Fixed. Look, there goes another squirrel!

[dldebertin]

So if we have a bunch of cars with VIN numbers assigned after Jan 1 1969 but still with 327 engines, do the Trim Tags on any of them say 01A not 12D? Now THAT is the real question.

I WAS under the impression that this all was related to the fact that the 327 engine did not meet pollution requirements that went into effect Jan 1 1969, but that the 307 engine did. Of course the 307 also lost 10 rated hp 200 vs 210 and generally is not seen as the greatest small block V8 Chevrolet ever built, whereas the 327 is something different from that entirely!

Part of this involves the deal GM must struck with the EPA regarding the dates over which the new standards applied barring the 327 as installed in 1968 and how the transition was carried out so all cars could be sold.