Hi
Can someone please explain to me how the date codes work. Sorry but I am confused

 

It depends on the part you are looking at. Some were on a calendar year basis and others were on a model year basis. The NCRS spec guide ($20) will tell you which system was in use for what component.

53-67 Pocket Spec Guide

68-82 Pocket Spec Guide

 

Everything was dated differently.

Flint engine castings used a letter for the month, one or two numbers for the day, and usually a single number for the year ("7" for 1967). Tonawanda castings were similar, but used two numbers for the date (67 for 1967). On castings the letter for the month follows the calendar year ("A" - January, "B" - February, etc).

Dating on trim tags use a letter for the month and two numbers for the day, the year is left off. Trim tag dating follows the production and model year. If 65 production started in August, a body with a date code of B16" would have been assembled September (B) 16th. On 64-67's bodies came from both St Louis and AO Smith in Michigan. In 64 and 66 the production of bodies began in different months at the two plants, so the letter for the month is different depending on where the body was made. 63 trim tags use a unique to 63 date, with a letter for the month and 1-6 for the week of the month.

Dating on the engine stamp pad used four numbers for the date, "0221" would be February 21st.

Early Holley carbs used a three digit date, year, month, week. 782 would be a Holley made in 1967 (7), August (8), the second week (2). Later Holley's use four digits, three digit for the day of the year, and a forth for the year. 0131 is a Holley assembled on the 13th day of 1971.

Some parts use a simple Julian date.

Transmission casting dates used a letter for the month, but they didn't correspond to the calendar, while transmission stamped dates do follow the calendar.

Stamped dates on certain parts like alternators, skipped the letter "I", using "J" for September instead.

These are just some examples, and GM didn't always follow the same patterns. I'm not even sure I posted all of these correctly, as it can be a real challenge to keep track of how everything was dated.

 

As you see from the above, GM did not set date code format for all vendors...many of whom adopted standard systems like Julian but then others used other dating systems. NCRS spec guides and technical information manuals attempt to provide those formats by part.

Hope this helps!

 

I can see how the OP could be confused.
I'm just glad these things mean nothing to me.
Life is way to short to be worried about numbers no one ever sees.

 

Ahhhhhhh..
and god said.."Let there be light"

Thank you now I get it

 

If it was true that nobody ever saw them then nobody would be worried about them.

 

As long as the date codes are a "thing", they will have value associated with them. Personally, I believe that after 50+ years, many of the Top Flight cars likely have parts with 'creative' date coding on lots of parts. Original factory parts (except for major castings) all 'die' eventually.

 

Yes , and people hunt for and then spend ridiculous money for a Alternator case with a "Correct " date code. Doesn't mean it's the alternator that came on the car. Just trying to fool people that it is.
And of course the general public when looking at cars at a car show always look for these numbers and letters and are truly impressed.

 

I don't think anyone is trying to "fool" anyone into thinking a part is the original part delivered on a car, just by finding a right date coded part. And what business of your's is it if they do? People have the right to spend their money any way they want, and if it's their car and they want to restore it as close as possible as to how it left the factory, so what? What effect does it have on you and your life, and why do you care?

I'm sure if we met you wouldn't care much for me. I've been an NCRS judge for years and have an NCRS Top Flight car in my garage. Guess what, I also have a car with the wrong engine, Holley carb, intake, headers, mags and other modifications. Worse then that, I spend a lot of weekends working on a 65 Corvette vintage racer that beyond the frame and parts of the body, doesn't have much else left on it from 1965. Unlike you I can appreciate all cars, both modified and restored.

Playing with Corvettes is a hobby, and I've never understood why some people have such a strong need to belittle and attack others in the hobby, just because they chose to enjoy it in a different way.

I'm too am glade that "these things mean nothing" to you, but IF they don't, why did you feel it was necessary to come on here not once, but twice, to attack people who do have an interest in them?????

My apologies to the OP for my rant, and for taking this so far off topic.

 

What are you actually judging? Cars that are made from all sorts of parts...original, salvaged, aftermarket, homemade...for the purpose of "looking" like an original factory car? I don't get it. But, lots of folks are into that process. Whatever "floats your boat".....

 

hmm

 

Great Job on the Research!

 

Maybe I'm the only one, but a car with its born components just makes me somehow happy and amazed. I recently did an extensive engine bay resto on my 72 with matching motor and finding the original dated things like wiper motor, blower motor, vacuum lines and even the tranny mount which was dated and original was nice and amazed they still work with the car they were born with. But I had to get some ram horns to replace the headers and did not seek out date correct ones. I can appreciate all sides of the hobby from survivor, full numbers resto, to heavily modified. Keeps up the interest in these cars.