As many of you know the Julian date code system was employed to date the day of manufacture beginning with the "814" 1963 "W" block. Prior to that Chevy used the more conventional system showing the month and year of casting. I've just done a great deal of research on this to get information about my car and I want to share this on the forum so nobody else has to go through what I just did.
My greatest problem came from not recognizing the actual date code on my engine because it was only two[2] digits. Every proper explanation of the Julian Date Coding system I found calls for a three digit code in all cases. Thus, an engine casting on say February 15 would properly be coded 047 allowing 31 days for January and 15 more for that date in February. HOWEVER, that's not the way the boys at the foundary actually did it!
In the case of my engine it was coded "23" and that translates to January 23. I see no problem with them doing that but my job sure would have been a lot easier if I knew they did not use zeros in front of the numbers. I'm guessing now, but I suppose a single digit number is also possible here to account for those casting dates between January 1st and January 10th, 1963.
I need to give credit here to that OLDSKYDOG - Cecil who posed the following in a different thread>>>oldskydog Dec 12, 2009
"Just a minor technicality, but julian date codes were not always 3 digits. Zeros were not placed in front so the first three digit date code would be 100. January 1 would be julian date code 1."
If I would have seen Cecil's words earlier it would have saved me a lot of work.
Retrieving the casting date code off an engine that is still in the car is no picnic. My little wife Patty spent a lot of time actually laying across the fender and on top of my 409 engine padded with towels trying to do this. Until we discovered our best method she got the number by using a mirror and her digital camera. I want to caution anyone doing this to be careful when translating the mirror image but also to be even more careful about cleaning the casting numbers with a small wire brush. As we cleaned it up our actual number "23" was first a 28 and then a 29 as the dirt was progressively cleaned out of that tricky #3 cast number.
Regarding the best method to find/see these numbers, ours turned out to be a camera and tiny 6 inch TV system we had for underwater inspection work. This is something you can buy for about $60 at Harbor Freight but its a black and white only model. They also have a color model for about a hundred bucks. I think any decent security camera hooked up to a TV would work just as well. Of course you can also purchase a special remote inspection device and any of these alternatives should be just fine... they beat having to pull the engine, that's for sure!
All the best,
BuzGuy at Harveys Lake, PA.
PS: I am doing this as part of an attempt to get my car documented for the National Impala Association through Jersey Late Greats, Inc. Tommy Nolan hooked me up with them and they sure do appear to know what they are doing.
PPS: Julian Date Coding is not used all the time
My greatest problem came from not recognizing the actual date code on my engine because it was only two[2] digits. Every proper explanation of the Julian Date Coding system I found calls for a three digit code in all cases. Thus, an engine casting on say February 15 would properly be coded 047 allowing 31 days for January and 15 more for that date in February. HOWEVER, that's not the way the boys at the foundary actually did it!
In the case of my engine it was coded "23" and that translates to January 23. I see no problem with them doing that but my job sure would have been a lot easier if I knew they did not use zeros in front of the numbers. I'm guessing now, but I suppose a single digit number is also possible here to account for those casting dates between January 1st and January 10th, 1963.
I need to give credit here to that OLDSKYDOG - Cecil who posed the following in a different thread>>>oldskydog Dec 12, 2009
"Just a minor technicality, but julian date codes were not always 3 digits. Zeros were not placed in front so the first three digit date code would be 100. January 1 would be julian date code 1."
If I would have seen Cecil's words earlier it would have saved me a lot of work.
Retrieving the casting date code off an engine that is still in the car is no picnic. My little wife Patty spent a lot of time actually laying across the fender and on top of my 409 engine padded with towels trying to do this. Until we discovered our best method she got the number by using a mirror and her digital camera. I want to caution anyone doing this to be careful when translating the mirror image but also to be even more careful about cleaning the casting numbers with a small wire brush. As we cleaned it up our actual number "23" was first a 28 and then a 29 as the dirt was progressively cleaned out of that tricky #3 cast number.
Regarding the best method to find/see these numbers, ours turned out to be a camera and tiny 6 inch TV system we had for underwater inspection work. This is something you can buy for about $60 at Harbor Freight but its a black and white only model. They also have a color model for about a hundred bucks. I think any decent security camera hooked up to a TV would work just as well. Of course you can also purchase a special remote inspection device and any of these alternatives should be just fine... they beat having to pull the engine, that's for sure!
All the best,
BuzGuy at Harveys Lake, PA.
PS: I am doing this as part of an attempt to get my car documented for the National Impala Association through Jersey Late Greats, Inc. Tommy Nolan hooked me up with them and they sure do appear to know what they are doing.
PPS: Julian Date Coding is not used all the time