With enough VINs we should be able to determine what batches of cars were produced & when like the B & E body guys can do these days.
I have over 9,200 1969 B bodies on file across all four plants and I have data bases for all plants covering the 1969 model year. So, I'm one of those 'guys' that can offer insight into data bases.
Accumulating enough data to be valid is incredibly time consuming. I've spent 20+ years doing what I do and have not even reached 10,000 cars on a year that included 80K+ Road Runners alone, plus Chargers, plus other muscle cars, plus garden variety four doors and wagons, etc.
I grab data from all A, B and C bodies for most years. 1970 Newark cars are some of the hardest to find. The highest '70 Newark VIN I've seen is 266XXX meaning there were only ~166K cars assigned that year. That's relatively low number of cars. Production numbers were similar to the LA plant but LA cars have a much higher survivability rate possibly due to where they were sent (the south and south west) plus they were mostly more desirable B and E bodies (for 1970) that kept better. C bodies sent to the NE probably didn't have the likelihood of surviving the weather and desirability factor.
A data base helps call out bad tags as one can see what is coded and when during the year. Bad tags on C bodies is not as prevalent as on B and E bodies.
A data base helps bracket engine and transmission assemblies when they are separated out of a car. A data base will give you some guidance if the assembly is out of a Dodge, Chrysler, or Plymouth.
With enough data, one can begin to see the relative distribution of colors and options once the data base reaches a level of stability and factory records do not exist.
A data base tells you what VINs were assigned to which makes and, usually, the related SPDs. One can see scheduling consistency, or inconsistencies, during a model year. You'll find interesting glitches in scheduling.
A data base does not tell you ANYTHING about production other than relative position within a model year. (there's plenty of info out there on the lack of correlation of VIN to production)
I think what you are doing is incredibly noble and necessary within the hobby. I applaud and encourage you. Someone
should be accumulating data on C bodies like the B & E body guys do. It's needed but it will not be as easy for you as as it is for them.
