Quadrajet Date code

[Harold# 43147]

I have a customer that asked me if I had a Rochester Quadrajet for his 1969 427 390 HP M/T. he was looking for a 7029215 carb for a Sept. 1968 production Date. I told him that Rochester dated there carbs from Jan.-Dec and most GM production was from Aug.-July so the correct Carb would be a 7028219 with a Sept. Date. He said his books showed it should be a 7029215. I have been restoring Quadrajets for about 5 years and have been rebuilding them for over 20 years. I know you guys can get this issue straight.

[D S.]

Re: Quadrajet Date code

My 7040204 is the correct carburetor number for my 454 TH400 application and has nothing to do with dates. There is usually another number next to it like a four digit number such as, using mine for an example again, 0055 which is the 55th day from January 1. I believe the date code your customer would be looking for is the number of days from January 1 to September 1, something like 0235. Certainly there will be other responses to your post and my answer.

Thanks,
Scott

[Patrick H.]

Re: Quadrajet Date code

7029215 is the correct number he is looking for.

Scott is correct that there should be a 4 digit date code next to that, assuming it's a Rochester-built carb. For the occasional Carter-built Rochester Quadrajet (there are a few) it is a 2 digit code.

What you're looking for is a code of DDDY where the DDD is the Julian day of the year (001 through 365 or, for a leap year like 1968, 366) and the Y is the year of manufacture; 8 in your case. So, he's looking for a date code prior to the build date of his car. Monday July 1 is day 183 (it would be 182 but 1968 is a Leap year) for a code of 1838. Friday Sept 13 is day 257, for 2578.

I hope that helps.

Patrick

[D S.]

Re: Quadrajet Date code

Thanks, Patrick. You're correct. I knew I was forgetting something that had to do with the year designation in the four digit code. Mine is 0550, not 0055. 55th day, 1970.

[Harold# 43147]

Re: Quadrajet Date code

If the car was built in Sept 1968 and it was a 1969 model and the 7029215 carb was not built until Jan 1969 then there is no way it could be correct for Sept 1968 built car. The 7028219 wich was built from Jan-Dec 1968 should be correct does this make sence??????????????????????

[Patrick H.]

Re: Quadrajet Date code

Harold,

Carburetors are built by MODEL year, not calendar year.
So, 7029215 carburetors were being manufactured as early as July, 1968 for the 1969 MODEL year Corvettes that began production later that year (September of 1968).

Patrick

[Harold# 43147]

Re: Quadrajet Date code

I will have to disagree with this I have been doing more research with the camaro/chevelle web sites and they all concour the Julian date system for Rochester. I had one email response that said this info is in 1969 resoration book that is sold through NCRS store does any one have this book and could confirm???????????????

[Patrick H.]

Re: Quadrajet Date code

Harold,

We've been TELLING you the date system. It's the same as what you're trying to get at, whether you want to call it Julian or whatever. The Julian date code is the DDDDY format.

And yes, the info I'm giving you is straight "from the book." It's laying on my desk here next to me.

I'll put it back on you - If a 1969 model year car is built in September, when do YOU expect the carb to be built?

Disagree all you want, but put a wrong numbered carb or a January dated carb on a September car, and you'll lose points.

Patrick

[Harold# 43147]

Re: Quadrajet Date code

Patrick I will give a example and you tell me what you inturpet.7029215 carb was never built until Jan 1 1969 so there is no way that a 1969 model corvette built Sept 1968 could have this carb on it. They never made it until Jan 1 1969.The correct carb for this should be 7028209 wich was built from Jan 1 1968-Dec 31 1968. Does this make sense?????
Harold

[Michael W.]

Re: Quadrajet Date code

My experience is the same as Patrick's.

What is your source that says a 7029215 carb could not have been built before Jan.1 1969?

[Dick W.]

Re: Quadrajet Date code

Harold, I think that you are comparing eggs and apples, or oranges and bananas.

The 7028219 carb was installed on the 327-350 engine with 4 speed in model year 1968. The 7029215 carb was installed on the 427-390 engine with 4 speed in model year 1969. The calibrations of the two carbs are totally different. I do not know what your source of information is but apparently it is in error if it tells you that the 7029215 was manufactured only in calenday year 1969. This carb is documented on 1969 MY cars from August 1968 through December 1969. This is spelled out in the 1968-69 Technical Information Manual and Judging Guide available for purchase at the NCRS Bookstore on this site

[Harold# 43147]

Re: Quadrajet Date code

I stand corrected I made a typo 7028209 M/T 427. One source I found to day was 1969 stingray guide book which states julian date code. I will post the other sources off internet later. If for example that a 7029215 0978 date how would know if this was made in 1968 0r a service replacement made in 1978?????? I appreciate your guys input I am not trying to make people mad just want proof positive what the date system was.
Dick thanks for your response and correction.
Harold

[Patrick H.]

Re: Quadrajet Date code

"If for example that a 7029215 0978 date how would know if this was made in 1968 0r a service replacement made in 1978??????"

Harold,

You couldn't tell, but, um, who really cares??? Either way it would "pass" for 1968 and that's all that counts. 0978 seems a little early in 1968 as it's April 7th AND a Saturday, but you may have just been giving us an example and not a real carb date.
In actuality, the 7029215 was not being made for service in 1978, so the odds of it being made in 1978 are somewhere between zero and none.

To address your other post, I don't know what your source of information might be, but 7029215 carburetors were absolutely, positively being made before January 1 of 1969.

Patrick

[Harold# 43147]

Re: Quadrajet Date code

We might be getting to the end of this my sources do not state that the 7029215 was not produced in 1968 they just state that Rochester used a Julian date system Jan-Dec. Then a correct Date code for a car built Sept 1968 would be 7029215 2538 this would be Sept 10 1968 give or take I think 1968 was a leap year. I thought that GM had to produce parts for 10 Yrs so this would make service replacement carbs in 1978 possible??????.Is the date code of no importance for NCRS judging on carburetors just the correct # is required??????
Thanks for your response

[Patrick H.]

Re: Quadrajet Date code

The 10 year supply is somewhat Urban Legend. In addition, if a Q-jet made in 1975 (or whenever) would WORK on the car, that's close enough.

Yes, the date matters, but as we can't tell if it's a 68 or a 78, just an 8, so you would get full credit.

Patrick