Recent Posts

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91
Quadrajet Carb Talk and Tips / Re: wings on my base gasket
« Last post by guero_gordo on February 23, 2025, 07:52:41 PM »
Four holes that perfectly match the holes in the carb and manifold, except for the quarter-moon protrusion into the secondaries, and orientation of the gasket is the problem here?
92
Diagnose a Quadrajet carburetor problem / Not sure what my Carb problems are
« Last post by AdamC on February 23, 2025, 12:50:30 PM »
I recently bought a 1970 c10 with a 7045228 quadrajet.  The truck ran awful, so we pulled the carb and cleaned it out.  Before finding this place, I had bought a rebuild kit online, so has all new gaskets, piston pump, and vacuum "covers".  I also added an electric choke since the previous owner had removed all choke components and just hand fed fuel to the primaries until it was up to temp.  Since putting everything back together, it runs fair at idle, but if you do more than ease on the accelerator, it stalls.  I tried tuning with a vac gauge and the highest reading I got was 3 in Hg.  when adjusting the right side idle mixture screw, no turns either direction changed the reading.  I also noticed that after running a bit, if I shut off, the left side primary looks wet, but the right side looks dry.  I am a total newbie, but my daughter wanted her first vehicle to be a project truck for us, so any and all help would be greatly appreciated.
93
Quadrajet Carb Talk and Tips / Re: wings on my base gasket
« Last post by Kenth on February 22, 2025, 04:24:42 AM »
It is clear that the gasket is installed in the wrong direction.
94
Quadrajet Carb Talk and Tips / Re: wings on my base gasket
« Last post by guero_gordo on February 21, 2025, 09:52:00 PM »
Well, them small holes are in the front, and the big'uns in the back...
95
Quadrajet Carb Talk and Tips / Re: wings on my base gasket
« Last post by 77cruiser on February 20, 2025, 04:29:15 PM »
Looks like it's backwards.
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Quadrajet Carb Talk and Tips / wings on my base gasket
« Last post by guero_gordo on February 20, 2025, 02:53:30 PM »
I'm 75% sure this is from the rebuild kit I bought from Cliff
In any case, what do the flaps in the secondary bores on this gasket do, and should I just hack them off?

7040511 on sbc350 gen I
97
Quadrajet Carb Talk and Tips / Re: 17057512 factory specs
« Last post by Cadman-iac on February 20, 2025, 08:03:03 AM »
Quote from: novadude on February 19, 2025, 01:50:38 PM
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?
98
Quadrajet Carb Talk and Tips / Re: AFR dropping just off idle
« Last post by Cadman-iac on February 20, 2025, 07:00:14 AM »
 No, there's no nozzle drip, I've checked it for that and to see when it begins to pull from the main system.  I don't remember exactly when it begins pulling from the main system, I want to say around 1200 to 1300 rpm, but I've slept since I checked and my memory resets every night after the reboot.
 As for throttle position, I haven't tried to see how much farther it will close, but if it's not there now it's almost there, so I don't think that's an issue.
  I did enlarge the mixture screw holes to .078 to try to eliminate the off-idle lean condition it had. That's not nearly as bad as it was now.
 The more I drive it and watch the AFR gage through the various rpms and loads, the more I think I understand what is going on. I just want to be sure I'm not misinterpreting what I'm seeing.
 I couldn't really tell how fast the engine was running because my old tachometer was bouncing and I couldn't get it to clear up, so Tuesday I got my new tachometer from Summit Racing (made in America)  and I can tell much better what's going on.
99
Quadrajet Carb Talk and Tips / Re: 17077230 jet/rod sizes from the factory
« Last post by Cadman-iac on February 20, 2025, 06:36:43 AM »
Quote from: Kenth on February 20, 2025, 01:06:57 AM
I have found that 1977-79 Cadillac 425 units has about .078" lower air bleeds and about .049" idle needle holes.

 Yep, you're right, I must have written it down wrong when I copied my notes and didn't catch that.  I guess I need to verify that now to be positive.
100
Quadrajet Carb Talk and Tips / Re: 17077230 jet/rod sizes from the factory
« Last post by Kenth on February 20, 2025, 01:06:57 AM »
I have found that 1977-79 Cadillac 425 units has about .078" lower air bleeds and about .049" idle needle holes.
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