66 Hooley carb date code

[Robert M.]

For a base engine 1966 Holley 3367 carb can it have a four number date code or were they all three number date codes? Also how close to the engine build date can the date of the carb be? My engine build date is F0516(May 16). The carbs I have seen have a 653 (3rd week of May 1966) which would put it in the same week as the engine assembly date, and a 0376 (Feb 1966) dates. The carb I have is the correct Holley but it has the wrong date of a 1970 build date. It needs to be rebuilt so I am thinking of getting a correctly dated carb. Any thoughts would be appreciated. Thanks, Bob.

[Mike M.]

Re: 66 Hooley carb date code

For a base engine 1966 Holley 3367 carb can it have a four number date code or were they all three number date codes? Also how close to the engine build date can the date of the carb be? My engine build date is F0516(May 16). The carbs I have seen have a 653 (3rd week of May 1966) which would put it in the same week as the engine assembly date, and a 0376 (Feb 1966) dates. The carb I have is the correct Holley but it has the wrong date of a 1970 build date. It needs to be rebuilt so I am thinking of getting a correctly dated carb. Any thoughts would be appreciated. Thanks, Bob.

all 66 hollys were dated with three alpha-numerics. it wasn't tillthe early 70's that the four digit dates were stamped. i like to see the holly date code a month or two prior to the engine assembly date.mike

[Jack H.]

Re: 66 Hooley carb date code

On dates, understand the engine plant(s) test fired and shipped engines WITHOUT carb attached/installed. The carb met up with the engine at the power train feeder line to the final assy process where the car was assembled.

So, there's not that much correlation between the engine assy date and the carb assy date. That's especially true of 'exotic' engines that had a limited/low useage rate (say, L88)...

You go by the car's final assy date, dictated by the VIN, to assess carb date validity. The general guideline is 0-6 months prior to the car's final assy date for this and other/similar engine 'bolt on' items like alternator, starter, Etc...

[Robert M.]

Re: 66 Hooley carb date code

Thanks guys. In corvette by the numbers the author states Holley carbs were dated with both the 4 number system and the 3 number and 3 alphanumeric code prior to 1972, then after that only the 4 number code was used. I was confused because in the 66 judging guide it states only the 3 alphanumeric code and not the other two ways of date coding. All the supposed correctly date coded carbs I have seen for sale have the 3 or 4 digit code not the alphanumeric code, this is where I got confused(it's very easy to confuse me). So if I understand correctly then ONLY the alpha numeric code is acceptable or are the other two ways of code dating ok as well. Thanks, Bob.

[Rob M.]

Re: 66 Hooley carb date code

Robert,

The date coding for your carb should be 3 digits - alpha-numeric. The first digit would be the year - 5 (1965) or 6 (1966). The second would be month - 1 thru 9 for Jan. - September and then "O" for October, "A" for November, and "B" for December. The third digit would be week of month - 1 thru 5.

My May 6th, '66 300 horse is dated "643"

6 months prior to your car build date works for judging, however I would expect a date 2 to 8 weeks more "typical" for your car.

Good luck

[John H.]

Re: 66 Hooley carb date code

Thanks guys. In corvette by the numbers the author states Holley carbs were dated with both the 4 number system and the 3 number and 3 alphanumeric code prior to 1972, then after that only the 4 number code was used. I was confused because in the 66 judging guide it states only the 3 alphanumeric code and not the other two ways of date coding. All the supposed correctly date coded carbs I have seen for sale have the 3 or 4 digit code not the alphanumeric code, this is where I got confused(it's very easy to confuse me). So if I understand correctly then ONLY the alpha numeric code is acceptable or are the other two ways of code dating ok as well. Thanks, Bob.

Bob -

Through 1972, Holleys were dated with three digits; the second digit could be a number or a letter, depending on the month. After 1972, they were dated with four digits in a Julian format (day of the year followed by the year).

Any Holley on a Corvette with a 4-digit date code is a Service replacement carburetor.

[Robert M.]

Re: 66 Hooley carb date code

Thank you guys, that clears things up.

[Ronald L.]

Re: 66 Hooley carb date code

With all due respect, the Holley's went on at the factory and had absolutely no correlation to Engine build date.

Suggestion is this. Poll known original cars, un molested with known original carbs within 500 to 1000 vin's of your serial number to know how the factory, St Louis was running on dated parts out of Holley. MFG, the were pretty close to each other, so transit time was not as long as people think. If your car was very early or at the tail of production, like the last week - anything could happen, but was not normal in the middle of the model year.