[elcamino]

This is for all cars built at the factory, not just the Chevelle's (this might only be the 10,000 Chevelle off that assembly line)...

This statement I don't believe is accurate. The VIN count were only within models. The other cars like Impala etc ran down different lines within the same plant. So, its the 23,456 Chevelle model and would not include GTO etc. This is evident when you observe the last 6 digits of the VIN's. If it included all cars, VIN numbers would be very high and they are not.

Also other GM divisions, Pontiac Firebird for instance used the VIN sequence to ID the base engine, V8 started at 1000001 and L6 started at 600001.

 

[elcamino]

Prior to 1968 VIN derivatives were on high performance and optional engines mainly. These engines were deemed more valuable and saw increase theft of the cars for engines. In 1968 it became a federal law and all manufactures had in place them at inconspicuous places on the engine, trans, body and frame.

These VIN derivatives were unknown to all but insurance investigators and law enforcement at the time. It was a big aide in cracking down on car and parts thefts because they could prove that engine came from a stolen car.

Now days the VIN's are burned into the vehicle's computer.