Carburetor id number question
Thread Starter
Racer
Joined: Jan 2007
Posts: 256
Likes: 3
Carburetor id number question
I have a Rochester Quadrajet. I looked at the decode sheet, but am a bit confused. My carb has 7041208 DN and then 1763 underneath. I am confused b/c 704 tells me it is 1970-1975. The 1 means 1971 which is exactly what my car is. I have also been told, however, that the 1763 means 176th day of 1973. Is this correct? How can the top number indicate 1971 and the lower number equal 1973. Someone please explain how to read these numbers.
Melting Slicks
Joined: May 2006
Posts: 3,438
Likes: 41
From: Raleigh NC
St. Jude Donor '13-'14
I have a Rochester Quadrajet. I looked at the decode sheet, but am a bit confused. My carb has 7041208 DN and then 1763 underneath. I am confused b/c 704 tells me it is 1970-1975. The 1 means 1971 which is exactly what my car is. I have also been told, however, that the 1763 means 176th day of 1973. Is this correct? How can the top number indicate 1971 and the lower number equal 1973. Someone please explain how to read these numbers.
Thread Starter
Racer
Joined: Jan 2007
Posts: 256
Likes: 3
okay. How do I know if a unit is made for a corvette? Which number designates that so in trying to get a carb for this car I will know I am getting the right thing? This was the carb on the car which was a rebuilt carb exchange many years ago. Obviously someone did an exchange for a light truck carb and not a vette carb.
Team Owner
Joined: Jul 1999
Posts: 26,545
Likes: 46
From: Huntersville NC
According to my little black book, 7041212 if it is an automatic and 7041213 if a 4spd. GM used the same number Qjet carbs (I believe they were the exact same carbs) on multiple models except in 1968 when the corvette numbered Qjets were only used on vettes. There used to be a website that gave you the various Chevy models that used a given Qjet #, but can't find it.
Ahhhhh!!!!!! i found it i found it!!
http://www.oemcarb.net/partlist.htm
It always used to be at a different URL ( website), all my bookmarks were this website, but now it is some turkey running for congress..
And it looks like the 71 corvette smallblock Qjet was only used on corvettes.
Ahhhhh!!!!!! i found it i found it!!
http://www.oemcarb.net/partlist.htm
It always used to be at a different URL ( website), all my bookmarks were this website, but now it is some turkey running for congress..
And it looks like the 71 corvette smallblock Qjet was only used on corvettes.
Last edited by PRNDL; Jun 17, 2012 at 06:21 PM.
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Race Director
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Instructor
Joined: Jan 2007
Posts: 135
Likes: 0
From: Western Loudoun County VA
From talking with Cliff Ruggles, to make most Q Jet cores applicable for Corvettes it is just a matter of rebuilding with the right jetting. I sent him some picks of my '74 non-corvette core and he made up a rebuild kit for me to reuse it on a '69 427/390.
@superdave269, his book explained that the CFM on the q jet is determined by application using the same core by changing the full open angle of the secondary air valves, reducing it from the typical 750 CFM. Cliff's book says to bend the valve stop until they can open all the way to perpendicular, mine were pretty far from perpendicular.
@superdave269, his book explained that the CFM on the q jet is determined by application using the same core by changing the full open angle of the secondary air valves, reducing it from the typical 750 CFM. Cliff's book says to bend the valve stop until they can open all the way to perpendicular, mine were pretty far from perpendicular.
CF JASOC Member
Joined: Feb 2006
Posts: 8,040
Likes: 34
From: Downtown Annapolis, MD. The Future is where we all have to live. Let's not screw it up.
St. Jude Donor '08-'09-'10-'11
My '71 also had a service replacement carb, one of the 1705s.
My build date (F09) made it difficult to find a correct 7041213 because of the 1970 GM strike. I found plenty that were late Jan and after with little effort.
It took 8 months to find a 2310 dated 7041213. Sent it out to be professionally rebuilt and it works great.
Hope your car was built later in '71. Good luck.
Mark
My build date (F09) made it difficult to find a correct 7041213 because of the 1970 GM strike. I found plenty that were late Jan and after with little effort.
It took 8 months to find a 2310 dated 7041213. Sent it out to be professionally rebuilt and it works great.
Hope your car was built later in '71. Good luck.
Mark
CF JASOC Member
Joined: Feb 2006
Posts: 8,040
Likes: 34
From: Downtown Annapolis, MD. The Future is where we all have to live. Let's not screw it up.
St. Jude Donor '08-'09-'10-'11
These guys rebuilt my Q-jet and I'm really happy with it and them.
They also have many vintage carbs for sale.
http://customrebuiltcarbs.com/
They also have many vintage carbs for sale.
http://customrebuiltcarbs.com/
CF JASOC Member
Joined: Feb 2006
Posts: 8,040
Likes: 34
From: Downtown Annapolis, MD. The Future is where we all have to live. Let's not screw it up.
St. Jude Donor '08-'09-'10-'11
Melting Slicks
Joined: Jul 2009
Posts: 3,264
Likes: 3
From: Vero Beach FL
I found this a few weeks ago "Rochester Quad number decode"
http://www.carburetion.com/quadnumber.htm
7028219
Prefix code. "70" will appear on all late '60's Rochester Carburetors.
76 and later will start with "170"
2 - Decade produced.
702 - 1960's
703 - 1060's with A.I.R.
704 - 1970-1975
1705 - 1976-1979
1708 - 1980's
7028219
Year produced.
8 = 1968
If the number was 7045219 then
5 = 1975
7028219 Model
0 - Monojet (1 bbl) Federal standards
1 - Two jet (2 bbl) Federal standards
2 - Quadrajet (4 bbl) Federal standards
3 - Monojet (1 bbl) California standards
4 - Two jet (2 bbl) California standards
5 - Quadrajet (4 bbl) California standards
6 - VariJet (2 bbl) Fed
7028219 - Division.
0, 1, and 2 all indicate Chevrolet.
4 - Buick
5 - Olds
6,7 - Pontiac
7028219 - Transmission most cases
Even numbers - Automatic Transmission
Odd numbers - Manual Transmission
DG Production Code.
1938 Rochester produced carburetor Date Code
193 = 193 rd Day of the year
1938 8 = Year 1968
Other
A8 o MM Carter Produced carburetor Date Codes
A= Jan
B= Feb
C= March
etc....
A8 o MM 8 = year 1968
MM Production Code.
This is provided as a general reference only please verify from other sources
http://www.carburetion.com/quadnumber.htm
7028219
Prefix code. "70" will appear on all late '60's Rochester Carburetors.
76 and later will start with "170"
2 - Decade produced.
702 - 1960's
703 - 1060's with A.I.R.
704 - 1970-1975
1705 - 1976-1979
1708 - 1980's
7028219
Year produced.
8 = 1968
If the number was 7045219 then
5 = 1975
7028219 Model
0 - Monojet (1 bbl) Federal standards
1 - Two jet (2 bbl) Federal standards
2 - Quadrajet (4 bbl) Federal standards
3 - Monojet (1 bbl) California standards
4 - Two jet (2 bbl) California standards
5 - Quadrajet (4 bbl) California standards
6 - VariJet (2 bbl) Fed
7028219 - Division.
0, 1, and 2 all indicate Chevrolet.
4 - Buick
5 - Olds
6,7 - Pontiac
7028219 - Transmission most cases
Even numbers - Automatic Transmission
Odd numbers - Manual Transmission
DG Production Code.
1938 Rochester produced carburetor Date Code
193 = 193 rd Day of the year
1938 8 = Year 1968
Other
A8 o MM Carter Produced carburetor Date Codes
A= Jan
B= Feb
C= March
etc....
A8 o MM 8 = year 1968
MM Production Code.
This is provided as a general reference only please verify from other sources
Thread Starter
Racer
Joined: Jan 2007
Posts: 256
Likes: 3
Thank you all very much for your help. I have been on business traveling all week and apologize for not responded to all of your efforts sooner. I now know what I need to do and really appreciate your help! I hope I can be of help to you guys some time in the future.