Q-Jet ID

[ctrain22]

Can anyone tell me the application for this Q-jet?


First picture is stamping on back of carb, the second is on side above secaondary throttle shaft.

[stlbluesbrother]

Looks like an Oldsmobile 1969 Quadrajet (4 bbl) for an automatic tranny car. The guru's can confirm or dismiss my assessment.

[stlbluesbrother]

2 = 1960's
9 = year produced, therefore, 1969
2 = Quadrajet (4 bbl) Federal standards
5 = Oldsmobile
0 = automatic transmission (even number)

Not sure what the 'NF' designates.

[svnt442]

That even number bussiness is gonna make me nuts. That is a MYTH.

The correct number carb for my 1970 442 w/ auto is 7040257.
The W31 carb with or without AT is 7020455.
The standard 350 carb with or without AT is 7020450
These are all 1970 numbers, but don't assume that just because it ends in an even number it's for an AT equiped car.

I'm guesing that giving how they did it in 1970 that that carb could heave been on either an auto of manul equiped car. I'm also guessing it was on a 350. I don't have a 69 manual so I can't look it up.

[johnta1]

The correct number carb for my 1970 442 w/ auto is 7040257.
The W31 carb with or without AT is 7020455.
The standard 350 carb with or without AT is 7020450
These are all 1970 numbers, but don't assume that just because it ends in an even number it's for an AT equiped car.

The 7020450 should be 7040250 and the 7020455 should be 7040255.


It appears Olds had some carbs that were for all trannies, such as the ones mentioned above.

Might try my Carb Search for some carb numbers:

Carb Search

[svnt442]

That's what I get for letting my fingers move faster than my thoughts.....

[rcorrigan5]

29250 NF 0859: Olds Rochester quadrajet. Depending on when/where the carb was manufactured, others might have the markings 7029250 NF 0859 - they came both ways. The "250" quadrajet was used on the 350ci engine in 1969, with auto or manual transmission, and with or without A/C (see '69 Chassis Service Manual, page 6M-74). I've heard that the two letter code (NF) is some sort of "broadcast code", whatever that means. The Chassis Service Manual seems to indicate that NF is an assembly plant code (page 6M-27). The last 4 numbers (0859) indicate the julian date when the carb was assembled - the 85th day of 1969. It's an original carburetor - not a service replacement (the service replacement carbs don't have the "broadcast code" and the assembly date code is after the model year to which the carb belongs). If the carburetor is not for your car, I'd say keep it anyway. I had this same carb for a 1970 Cutlass, in a box, all completely apart, and someone paid me $50 for it. Olds carbs are getting harder and harder to come by and, someday, someone out there is going to want a 350-4bbl carb for the Cutlass they are restoring that was built a month or two (or three or four) after the date on your carburetor!

[78cutlass]

do yourself a favor and call Sparky's Carb Svc. Greg/Bill will answer any Q-jet question you might have.