C2 Date Codes

[Jim38243]

Would it be reasonable to assume that an alternator is an original part if the date code on it is one day after the date code of the body built.
Example: Body Build - E 21 (December 21, 1964)
Alternator - 4 M 22 (December 22, 1964)
As I understand it the body build is simply the date it passed by that station on the assembly line not the date of final assembly. If this is true how then do you determine the final assembly date.
Thank You! in advance.
Jim

[Bill Clupper]

Re: C2 Date Codes

Final assembly dates are actually determined by the VIN, which is really tied to the chassis and drivetrain assembly. As the alternator is assembled to the engine as part of the chassis system build that date is all that would be significant. There is more variability in bodybuild vs final assy date than chassis (think of AO Smith bodies and the associated transportation.

[Jack H.]

Re: C2 Date Codes

The process of figuring out when a car was built is essentially one of interpolation. Take the difference between the ending VIN of the current month and the ending VIN of the prior month to compute the number of cars built in the current month.

Now, here's where the trick comes in, use the number of work days in the current month to figure out the production rate (cars/day). Work your way forward to your VIN to get the day of build.

There are books on this subject (Corvette Birthday Book), but I always refer to such computation as 'approximate' build dates. Why? Well, the system PRESUMES we know exactly how many work/build days there were each month, AND we have perfect knowledge of final line production flow.

What I mean here is we know about third shift/swing shift additions, overtime work days and line rate. The interpolation process presumes the line was NEVER sped up, slowed down or sporadically halted (bad assumption!). It also presumes there were constant work shifts/day which is an equally bad assumption in my book....

In my opinion, the interpolation method is accurate +/- 3 days (not all that cool on 'close call' dating issues....