Rochester/Edelbrock Quadrajet Information

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Nalanthi

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...so I saw that the 1406 had its own sticky, so I figure to myself "Why the hell not".

The Quadrajet has seen quite a few decades of production starting in the mid 60s and became GM's standard-issue fuel delivery system until the era of TBI engines when GM ceased production and Edelbrock was the one left to carry the stone for a bit longer.
Love 'em or hate 'em, countless millions were produced - but I found that any attempts to procure information on them was a trying experience when compared to the newer and still in production Edelbrocks, Holleys, etc.

Links and descriptions are provided below. Authors will be recognized and given credit where credit is due.


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Quadrajet Installation Manual
Author: Edelbrock
© 1994 Edelbrock Corp. This is a basic installation manual released for the Edelbrock #1910. This document contains the most basic information on the Quadrajet with an elementary troubleshooting chart.

Quadrajet Owner's Manual
Author: Edelbrock
© 2000 Edelbrock Corp. #1910. Affectionately known to me as: "The Gospel According to Edelbrock". If you own any other Edelbrock carb, then this manual should be extremely familiar to you - and is one of the best tools in your carburetor arsenal.
While Edelbrock discontinued the manufacture of their Q-jet line, they still offer parts that will work on both Edelbrock AND Rochester variants.

Quadrajet Jet Change Chart
Author: Unknown
This chart is raw data - an intensive list of diameter/area changes based on respective tweaks to jet size changes. This will save you from having to crunch numbers by referencing your current or prospective setup.

Common Problems and Solutions for Quadrajet Carbs
Author: Lars Grimsrud
Lars Grimsrud's document on common issues one could experience on a Q-jet. The format is cause-effect, illustrating a common issue and what behavior(s) are associated with said issue.

How to Tune a Quadrjet
Author: Lars Grimsrud
Lars Grimsrud's document on tuning a Q-jet. This is an extremely intensive document and masterfully written with any advanced information you want to know - primaries, secondaries, tuning, and carburetor identification.

Quadrajet Secondary Metering Rods
Author: Unknown
This is an all-inclusive chart on secondary rod ID numbers, technical specs, and GM part numbers.

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Quadrajet Tuning Notes
Author: Rick Johnson
This document seems to be a collection of notes and observations from the owner of a site called tootechracing.com on a Qjet project he was working on.

Problems With Commercially Rebuilt Quadrajets
Author: Lars Grimsrud
Lars' accounting of three scenarios on commercially-built Q-jets. Buyer beware.


More info to come in the future, I'm sure.
 
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BADAZ chevy guy

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Bookmarked this page. The biggest question I had for months was: Which Q-Jet had the right geometry for use with a 700R4? I figured it out eventually, but it was a thorn in my side for quite a while.
 

Nalanthi

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Bookmarked this page. The biggest question I had for months was: Which Q-Jet had the right geometry for use with a 700R4? I figured it out eventually, but it was a thorn in my side for quite a while.


I do believe that I have that information in my store.
From what I understand, there was a variant that GM made for autos and one for standards - but I'll keep you posted as I sift through these documents and organize them.
 

BADAZ chevy guy

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I do believe that I have that information in my store.
From what I understand, there was a variant that GM made for autos and one for standards - but I'll keep you posted as I sift through these documents and organize them.

Thanks, Nalanthi. I already figured it out though. It's just a matter of finding the right throttle side plate. I was just commenting that it took me forever to find the right information.
The top carb is the early model (used w/kickdown cable). The bottom carb is a later model with correct geometry for a 700R4. See the more pronounced "Hook" in the rear arm and lower throttle cable mounting stud at the top.
 

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Nalanthi

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Reference Lars' article "how to tune a Quadrajet". You'll find a wealth of information on what you have from that doc.
 

BADAZ chevy guy

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Reference Lars' article "how to tune a Quadrajet". You'll find a wealth of information on what you have from that doc.

I agree. He put a lot of effort into his writings and he has a great deal of knowledge.
 

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I can sticky this thread, but before I do, I'd rather title it right. How is it titled Edelbrock if it's for Rochester Carbs?
 

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I do believe that I have that information in my store.
From what I understand, there was a variant that GM made for autos and one for standards - but I'll keep you posted as I sift through these documents and organize them.

Oh that's why the difference, Auto or Manual. Good to know.
 

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I can sticky this thread, but before I do, I'd rather title it right. How is it titled Edelbrock if it's for Rochester Carbs?

Im thinking he's referring to the Edelbrock made and sold Qaudjets
 

BADAZ chevy guy

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Oh that's why the difference, Auto or Manual. Good to know.

Hold up. The 2 pics I posted are for early and late configurations, but BOTH are for automatic transmissions. The Manual transmission would have likely come with only half of the throttle plate. Seen below.

Also... I'm using National Carburetors photos only because they are clear and good for reference. Not necessarily as an endorsement.
 

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MonsterZ

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I still have my stock Q-jet on right now and my truck is a manual. I'll get some pics of it today when I swap on the Holley and post them for you if you like. I had an Eddy 1406 on it and it literally fell to pieces on me yesterday. I'm re-kitting both the Eddy and the Q-jet and shelving them for now, will sell the Eddy after I move in October.
 

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I was into Corvettes and a frequent visitor to the Corvette forum. Lars Grimsrud was a member also and started a program to offer loaner Quadrajet carbs to members. I sent a old QJ carb I had to the program and Lars rebuilt it and loaned it out. A few years later the carb show up at my door fully rebuilt with info of what it originally came off of and install instructions. I put it on a 76 350 3 speed c-10 I had and it ran great and never had a problem. It ran so well that when I sold the 76 I removed the QJ and replaced it with a Elderbrock 1406. The QJ is now sitting on my 78 454 and will fire up on the first or second try.

In my opinion his QJ rebuild skills is equal to that of Sean Murphy of SMI. I have an SMI carb and it also runs well right out of the box.
 

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