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-   -   Quadrajet Needle & Seat (https://classracer.com/classforum/showthread.php?t=70869)

Dean Feiock 09-02-2018 05:35 PM

Quadrajet Needle & Seat
 
What is the best needle and seat for a Quadrajet? This is for an Ashley stocker carb, return style fuel system, and 6.5 lbs fuel pressure.

Windowed - Non Windowed ?

Best diameter - .124" .125" .132" .135" ?

Best place to purchase and part numbers would be appreciated.

SSDiv6 09-03-2018 12:00 PM

Re: Quadrajet Needle & Seat
 
If you can find them, the Grose-Jet assemblies are the best.
Once in a while you can find them in Ebay.


Also, Jet Performance carries all sizes of QJ needle & seat assemblies.

monte385 09-09-2018 10:37 PM

Re: Quadrajet Needle & Seat
 
Edelbrock used a .149 in there 1910 Qjet. You can drill em & experiment.

nhramnl 09-11-2018 11:00 AM

Re: Quadrajet Needle & Seat
 
Dean Oliver would tell you to stay away from the .149 Edelbrock needle and seat. He says he has helped a lot of racers who were having acting rich/flooding-type problems simply by having them switch to a smaller, "traditional" orifice size. He helped me with a car that was so blubbery at idle and around the pits that it would actually smoke gray. I switched the needle and seat, verified the float setting (it was right) and I had a different car. Dean's theory is that the .149 passes so much fuel that it creates turbulence that prevents the float from seating properly, which obviously makes the car flood.

monte385 09-11-2018 11:09 PM

Re: Quadrajet Needle & Seat
 
He would know. I'd say depends on fuel pressure, I'm running .144 with 6-6.5 psi in my street car.

nhramnl 09-12-2018 07:21 AM

Re: Quadrajet Needle & Seat
 
Quote:

Originally Posted by monte385 (Post 572565)
He would know. I'd say depends on fuel pressure, I'm running .144 with 6-6.5 psi in my street car.



I agree completely and probably should have said that. Dean said that some carb/engine combinations seem to get along fine with the .149, but when somebody calls with a "No matter what I do, the damned thing acts real smoky rich at idle and at slow speeds", the first thing he asks them is "Do you have a "big" needle and seat in the carb?". If they do, he tells them to take is out and replace it with a smaller one. I was honestly skeptical of something that simple fixing my problem, but the problem literally disappeared. Dean has been my 4GC and QuadraJet guy for many, many years, and has never given me bad products or advice.

Chad Fergen 09-12-2018 01:03 PM

Re: Quadrajet Needle & Seat
 
Great topic Dean. I'm hearing "smaller" than .149. How much smaller? I know mine is bigger that the .125 as my 1/8 drill bit is loose. I will check it with pin gauges at work today(on break of course... ;) ) and let you know. There are several on ebay under "quadrajet needle".

Chad Fergen 09-12-2018 01:06 PM

Re: Quadrajet Needle & Seat
 
Quote:

Originally Posted by Chad Fergen (Post 572622)
Great topic Dean. I'm hearing "smaller" than .149. How much smaller? I know mine is bigger that the .125 as my 1/8 drill bit is loose. I will check it with pin gauges at work today(on break of course... ;) ) and let you know. There are several on ebay under "quadrajet needle".

One more question that might play into this. I see they have different weight floats. I would think that that might have some effect on the seating of the needle. Thoughts?

nhramnl 09-12-2018 03:42 PM

Re: Quadrajet Needle & Seat
 
Just call Dean direct and he'll evaluate what you've got and make a recommendation. Dean Oliver - 870-830-5470

Todd Hoven 09-14-2018 07:14 AM

Re: Quadrajet Needle & Seat
 
Quote:

Originally Posted by monte385 (Post 572408)
Edelbrock used a .149 in there 1910 Qjet. You can drill em & experiment.

That size can be very temperamental. Anything over 5 psi with that size can cause the carb to flood over at any time.

I found the .135 size with a window works well. Anywhere from 6.5 to 7.5 for fuel pressure works for this.


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