Like the factory before him, Hewitt also warned against using lubricants on the carburetor. Lubricants attract dirt, which can increase wear on moving parts.
It's clear that there are a lot of adjustments and modifications that need to be made during the rebuilding process. While a local shop may have the ability to rebuild certain parts of the carburetor, it likely lacks the skills and the tools needed to perform a proper restoration. My advice is, if you need your carburetor rebuilt, send it to a professional who specializes in such work. You may well find that the cost is the same as letting the corner garage do the job.
If you have any questions, you can always give the guys at Daytona Parts Company a call at (386) 427-7108, or visit online at www.daytonaparts.com. Thanks for your question, and good luck.
Q: I'm trying to figure out the exact date on my 1968 Holley carburetor. I'm confused by the letter “B” in the month-of-manufacture position, as I always thought this code was a number. Could it be a stamping mistake? I've enclosed a photo of the air horn with the stamping.
Andy, Via the Internet
A: Many Corvette parts were coded to show when they were cast or assembled. Holley carburetors have three distinct stampings embossed into the driver side, front vertical surface of the air horn.
The top stamping is a seven-digit GM part number that may be followed by one or two letters. Below the GM part number is the Holley part, or “list,” number. The stamping reads “LIST,” followed by four numbers. Some Holley carburetors have an additional number, letter, or combination of numbers and letters.
Below the Holley list number is the three-digit date code, which can be deciphered as follows:
The first number designates the year of manufacture, represented as the last digit of the calendar year. For your application, 8 = 1968.
The second number or letter is the month of manufacture: 1 through 0 for January through October, and then the letters A and B for November and December. For your application, B = December.
The third number represents the week of the month the carburetor was assembled (first through sixth). For your application, 5 = fifth week of the month. Some original-equipment Holley carburetors may be coded using a four-digit date code. These are usually service carburetors or replacement parts. On these units the first three digits represent the Julian calendar date (001 through 365, or 366 for leap year). The last digit of the date code represents the year of manufacture, represented as the last digit of the calendar year.
The system can seem daunting at first, but with a little work, you should be deciphering Holley date codes with a minimum of fuss.