Holley Carb Date Code Question
Thread Starter
Racer
Joined: Aug 2001
Posts: 401
Likes: 21
From: SF CA
Holley Carb Date Code Question
My reference book is out on loan to a friend. If memory serves me correctly Holley carbs have a LIST number, a GM part number, a date code, and maybe one other number (?). As I recall the date code is 3 digits, ABC, where A is the last digit of the year, B is the month, and C represents the week (1, 2, 3, or 4).
If I am correct, what is used for Oct., Nov, and Dec.?
If I am not correct what is the proper way to read it?
Someone trying to sell me a Carb tells me the date code is "2502." I have no idea where to go with that, I assume they are reading the wrong number.
Thanks
If I am correct, what is used for Oct., Nov, and Dec.?
If I am not correct what is the proper way to read it?
Someone trying to sell me a Carb tells me the date code is "2502." I have no idea where to go with that, I assume they are reading the wrong number.
Thanks
Drifting
Joined: Jun 2000
Posts: 1,596
Likes: 52
From: Southern NJ
C2 of Year Finalist (stock) 2019
Re: Holley Carb Date Code Question (BAD-L88)
There is a GM Part No, Holley List No and Date. I am not familiar wiht the other number. The date code for assy line is a three digit date. The first digit is for the year, the second digit is for the month 1-9 = Jan-Sept and 0=Oct A=Nov B=Dec, the third digit is the week of the month. 5A3 would represent 1965 - Nov - third week. The four digit holley date was used on service replacement carbs. The last digit is the year, digits one through three are the julian date for that year or the n'th day of that year. Your example of 2502 would be the 250th day of either 1972,1982 or 1992
Safety Car
Joined: Jul 2001
Posts: 4,456
Likes: 6
From: Spicewood, Texas, USA TX-Texas
Re: Holley Carb Date Code Question (BAD-L88)
According to NCRS' 1968-1982 Corvette Specifications Guide, a 69 L-88 carburetor should have GM part number 3925519 (it may be stamped with the entire number or just the last five digits). The Spec Guide also shows the carb model number is 4150 and Holley's part number as R4054A.
My 70 judging guide explains that Holley carbs were stamped with the GM part number or just the last five digits, several alpha characters indicating plant of manufacture, and a four digit Julian date code next to the GM part number.
As already explained, the first three digits of the Julian date is the day of the year, and the fourth digit is the last digit of the year of manufacture; e.g. since 1969 WAS NOT a leap year, "0599" would indicate February 28, 1969.
I believe the "2502" is a Julian date code, and if the GM part number is correct, then it has to be a replacement carb. The most probable year was 1972, and since 1972 was a leap year, it was probably manufactured September 6, 1972. If you are looking for a functional replacement it would be fine; if you are looking for a correctly dated carb, then continue the search.
My 70 judging guide explains that Holley carbs were stamped with the GM part number or just the last five digits, several alpha characters indicating plant of manufacture, and a four digit Julian date code next to the GM part number.
As already explained, the first three digits of the Julian date is the day of the year, and the fourth digit is the last digit of the year of manufacture; e.g. since 1969 WAS NOT a leap year, "0599" would indicate February 28, 1969.
I believe the "2502" is a Julian date code, and if the GM part number is correct, then it has to be a replacement carb. The most probable year was 1972, and since 1972 was a leap year, it was probably manufactured September 6, 1972. If you are looking for a functional replacement it would be fine; if you are looking for a correctly dated carb, then continue the search.
Thread Starter
Racer
Joined: Aug 2001
Posts: 401
Likes: 21
From: SF CA
Re: Holley Carb Date Code Question (Chuck Sangerhausen)
Thanks, clearly the carb I was looking at is a 1972 replacement carb and not for me.
There was another carb used on later L-88's, List 4296, GM part # 3955205. My car had this double pumper model on it and my books told me it should have the List 4054A. I checked with Kevin MacKay and he told me the 4296 number before I even mentioned it. It is correct for later L-88's. I just corroberated this with a 1969 issue of Car Craft magazined which details the L-88's change to the 4296 carb and it's GM part number.
Unfortunately my carb is dated 044, 4th week of April 1970. The carb I was asking about was billed as a 1969 carb, which it clearly isn't.
This board is the best!!!
There was another carb used on later L-88's, List 4296, GM part # 3955205. My car had this double pumper model on it and my books told me it should have the List 4054A. I checked with Kevin MacKay and he told me the 4296 number before I even mentioned it. It is correct for later L-88's. I just corroberated this with a 1969 issue of Car Craft magazined which details the L-88's change to the 4296 carb and it's GM part number.
Unfortunately my carb is dated 044, 4th week of April 1970. The carb I was asking about was billed as a 1969 carb, which it clearly isn't.
This board is the best!!!
1st Gear
Joined: Mar 2023
Posts: 1
Likes: 0
My reference book is out on loan to a friend. If memory serves me correctly Holley carbs have a LIST number, a GM part number, a date code, and maybe one other number (?). As I recall the date code is 3 digits, ABC, where A is the last digit of the year, B is the month, and C represents the week (1, 2, 3, or 4).
If I am correct, what is used for Oct., Nov, and Dec.?
If I am not correct what is the proper way to read it?
Someone trying to sell me a Carb tells me the date code is "2502." I have no idea where to go with that, I assume they are reading the wrong number.
Thanks
If I am correct, what is used for Oct., Nov, and Dec.?
If I am not correct what is the proper way to read it?
Someone trying to sell me a Carb tells me the date code is "2502." I have no idea where to go with that, I assume they are reading the wrong number.
Thanks
1387 means if you don't mind me asking 🤔
