quadrajet/performer intake sucking air - Team Camaro Tech
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post #1 of 7 (permalink) Old Jan 28th, 02, 07:12 PM Thread Starter
Join Date: Mar 2001
Location: midwest
Posts: 22

I had a carter afb and an edelbrock performer intake on my 327. I just rebuilt the quadrajet and put it back on. It runs better than the carter. But at the front corners it hangs over the flange a little bit. That's where it's sucking air. Someone told me I needed a different gasket in there, but there isn't any meat on the flange for it to press aginst. Maybe I need some fancy adaptor plate or something. If anyone knows anything about, the advice would be much apreciated.
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post #2 of 7 (permalink) Old Jan 29th, 02, 12:21 AM
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Join Date: Aug 2000
Location: DULUTH, GA.
Posts: 917

The Performer has a spread bore footprint and really you should have had a conversion plate with the AFB, but I have seen them work without one. So, you are need of an adapter plate...I think you can order from Edelbrock thru Summit. I think Mr Gasket carries one too.

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post #3 of 7 (permalink) Old Jan 29th, 02, 03:54 AM
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Join Date: May 2001
Location: Austin TX USA
Posts: 501

Algenard...I've gone through the same thing. Call Vic (Edelbrock)...for free, they'll send you a steel plate which is about 1/8 of inch thick that fixes the problem. Tell the tech desk that you have a late 60's Chevy q-jet and the mounting on the performer doesn't seal off the the complete bottom of carb which causes a (bad) vacuum leak. I had to fax Edelbrok a copy of the Q-jet mounting gasket to Edelbrock to show them that I wasn't crazy, but I finally got to someone who new what I needed. Good luck!
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post #4 of 7 (permalink) Old Jan 29th, 02, 02:00 PM
Join Date: Aug 1998
Location: Waldorf Md. USA
Posts: 3,281

If I am reading your post correctly, you have installed a Quadrajet carb on the manifold. If so there should be no adapters or special gaskets needed unless someone has modified the manifold. Try one of the thicker Q-jet gaskets like the ones that come on mid 80's pickups. Or have someone look in the Edelbrock catalog to see what gasket they recommend. There are a bunch of different Q-jet gaskets, you might have to search a bit to find the correct one. Also, make sure that the front bolts are not bottoming out in the intake before they actually tighten down on the carb.
The adapter plates etc are only for installing a square bore carb such as a Holley or AFB.
Hope this helps,

Bill Koustenis
Advanced Automotive Machine
Waldorf Md
1971 Chevelle "Heavy Chevy" original owner
1973 Z-28 ..one family car...Brother bought it new in 73
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post #5 of 7 (permalink) Old Jan 30th, 02, 03:57 AM
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Join Date: May 2001
Location: Austin TX USA
Posts: 501

Hey Bill,

On the late 60's Chevy Q-jet there's a trough in the carb's throttle plate that's in front of the primaries which extends outside the primaries. This a rough visual (the small oo's are the primaries...the 00's are the secondaries:


This carb will leak vacuum on end of this trough (where the line is), especally on the driver's side when used on the Performer or RPM Performer intake unless the plate I referred to is used (or perhaps a spacer).

Am I making sense?
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post #6 of 7 (permalink) Old Jan 31st, 02, 08:29 AM
Join Date: Sep 1998
Posts: 470

The AFB carb is a square-bore trying to go on a spread-bore manifold, so you absolutely need the adapter plate for this. It is just a simple plate like sleepy said that gose on the manifold first, then the carb sits on it. You can get it at a lot of parts stores for about $8.

Bill C.

Bill C.
Colorado Springs, CO

68 Camaro... someday!
71 Chevelle SS
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post #7 of 7 (permalink) Old Feb 3rd, 02, 03:13 PM Thread Starter
Join Date: Mar 2001
Location: midwest
Posts: 22

Thanks for the information. After I got the first reply to my question, I went and found an adapter plate that works. Today I put it all back together and it runs great. The plate I got is: Mr. Gasket #1932, carb adapter kit. It's universal, one way it adapts a quadrajet to any manifold, turn it over and it will adapt any carb to a stock quadrajet manifold. I would have liked to have gotten a thinner adapter plate, but I didn't check back to read the other responses. The quadrajet is running much better than my afb ever did. Thanks for the help.
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