Cliff's Quadrajet Parts and Rebuild Kits
General Category => Quadrajet Carb Talk and Tips => Topic started by: Cadman-iac on February 07, 2025, 09:22:52 AM
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I need all the factory settings/ specs for this please. I want to return it to original if possible.
Thanks
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Did you find the specs info data?
I cant find the data spec pages for all the carb numbers now either
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Here is what i have on the 17057512:
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Thanks Kenth, much appreciated.
What would the federal version of this have then? Would you happen to have that as well?
It's going to be put on a 78 454 that's all stock other than having been rebuilt with .030 oversize pistons. I didn't realize this was a California carb.
Thanks again.
Rick
Edit: I noticed that it lists the main nozzle size for this, aren't those all the same? I've never thought to check them before.
Can these be changed or are they permanently mounted and what you get is it?
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Main circuit nozzle air bleed at the end of yellow arrow. It is the same for all Chevy Q-jets.
As for the nozzle brass inserts there is different sizes for just about every manufacturer and even for certain applications that determins what jetting to be used.
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Interesting, thanks.
Can you post the federal specs for this carb, what would that be, a 17057212 maybe, if I read Cliff's book correctly?
Rick
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The 17057512 is used on California 1977 Chevrolet & GMC Truck 454 CUI engine Heavy Duty for M/T & A/T trans. C-10-20-30 PICK UP SUB P-30 MOTORHOME.
There is no 17057212, but there is a 17056212 for 1976-77 Truck M4MC for 454 Heavy Duty Federal usage C-10-20-30, P-30, MOTORHOME.
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That's perfect, thank you. I wasn't sure what the federal carb number would have been, so I took a guess.
Much appreciated Kenth.
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Kenth... your post about main nozzle air bleeds intrigued me.
Let's say you have a Chevy carb with the 0.029" bleed vs a Cadillac carb with an 0.050" air nozzle bleed. Assume all else is equal (the other two MABs, idle circuit, jets primary rods, etc). How would this affect the fuel curve? I would assume that the larger main nozzle bleed would delay start-up of the main system, and maybe require a larger main jet to maintain the same fuel curve? Just curious if you have any experience with how different main nozzle bleed sizes typically impact the calibration requirements in the rest of the carb? This is one area of a q-jet that I've not seen discussed often.
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Kenth... your post about main nozzle air bleeds intrigued me.
Let's say you have a Chevy carb with the 0.029" bleed vs a Cadillac carb with an 0.050" air nozzle bleed. Assume all else is equal (the other two MABs, idle circuit, jets primary rods, etc). How would this affect the fuel curve? I would assume that the larger main nozzle bleed would delay start-up of the main system, and maybe require a larger main jet to maintain the same fuel curve? Just curious if you have any experience with how different main nozzle bleed sizes typically impact the calibration requirements in the rest of the carb? This is one area of a q-jet that I've not seen discussed often.
I'd like to know how this affects the fuel flow too since I'm using a Cadillac carburetor on a small block Chevy. Is that nozzle bleed too big for a smaller engine?