I have yet to have been able to address the number on my Quad Jet 4bl which is installed in my 66 330/ 320 hp engine, 4 speed manual trans.Please advise what this denotes:

07041312
2778

Thanks for the help.
Wayne

 

Are you sure that number is right?

 

first 0 means nothing its a GM part number thing...they added another number..very common

7041312 is a service carb for 66 400 and 425 a couple of cadillacs and a few other cars according to a quick google

2778 is 277th day of 78 for 79 is production date

 

Koda, thats the number on the carb. The engine was built in 1980 with a fresh NOS 330 block, part number 393336, casting 381917 Large #1. Which now may make sense as per Mark. I could not find a decode so I am glad Mark found this info but from where, because I wasn't having any luck. Mark, which or how did you decode.? Engine also has a 390327 LG 6 intake manifold and 389394 LG 3 heads. The heads and intake manifold are stock for a 66 330 HC. Maybe some more info will show up. Thanks for the help guys.
Wayne

 

Actually, my foot thick Delco book only shows the 1966 Olds 400/425 application for this carb. Yes, it is a service replacement number. The associated catalog number is 24-551.

 

So thanks for the info guys. The carb is operating fine as far as I am concerned. I assume I have enough information now to get services or parts without much trouble.
Explain please how a carb like this can fit on a 330 correct intake and also be used on a 400/425 application.
BTW Joe I read your advice someplace about starting Q-Jet, three depressions of gas pedal etc. Sure starts nice now after sitting a week or two.
What is Associated Catalog 24-551?

Great help.
Wayne

 

All Qjets have the same bolt pattern. Within a given year, most use many of the same castings. The spreadbore design and secondary air valves that meter air and fuel based on engine needs make the Qjet an EXTREMELY adaptable carb. Keep in mind that GM used the same basic Qjet design on engines ranging from the 231 cu in Buick V6 to the 500 cu in Cadillac. In many cases, the primary side jets and metering rods are the same on both small block and big block applications (I was just looking this up for the 7041250 and 251 carbs). The secondary metering rods are the ones that were usually different for SBO and BBO applications. In your case, it means that your carb is probably a little rich at wide open throttle, which is where it is most forgiving. If you were ambitious, you could play with changing the secondary metering rods to improve fuel mileage a little.

That's just the catalog part number Rochester assigned to this service carb.

 

Thanks Joe, excellent information. Have yet to have my foot that far into it. I do feel a lot more comfortable with the set up. Appreciated.
Thanks
Wayne