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Discussion Starter · #1 ·
I have been thinking of possibly using a Quad down the road instead of the Holley 3310C. The biggest reason would be the increase in MPG...but with that said I have used them in the past and had decent performance out of them too. Whadda you guys think...also I see Edelbrock is making a "quad" carb now is it the same as the old ones or is it something different?

thanks
 

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The Edelbrock is the same as the Rochester units, just new. Even in stock form they perform really well. The primary side will get godd MPG and the secondary side when set up properly will flow plenty for max performance. I have a modified one going on the 400. I don't recall all that was done to it, but I do remember being told it will perform a lot better than it would have before the mods.
 

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Discussion Starter · #4 ·
SS 396 said:
Carter also made the QJ didnt they?
Joe
well carter made the thermoquads and stuff like that but i'm not sure if they made any quadrajets:confused:
 

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They did,after Rochester.Still a Good Carb.I have had good running Quadrajets,but they take some work.Remember the Spread Bore Holley.What about the QJ Replacement Holley made in the Mid 70's?
Joe
 

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Carter actually sub-contracted with GM to make Rochester Quadrajet carburetors for Chevy for a year or two when demand exceeded Rochester's capacity. But you are correct in remembering the version of a big and little that Carter made was the plastic body ThermoQuad used on RoadRunners and all of their factory hot rods.


Big Dave
 

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I have another Quadrajet question. I've got a model stamped "7042220", which decodes as being built in 1972. It's currently on a 1970 BB/402 engine. There's some hesitation when accelerating from idle and I will likely end up rebuilding it. (I've got Doug Roe's book...and will finish reading it before I start anything.) But, I'm wondering if there are any significant performance differences between the orginal 1970 model and the 1972 version that I have.
 

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Doug Roe was an original Q-Jet engineer and his book is the best I have ever seen. I spent a week with Doug once and many hours on the phone with him.
The 72 got some jetting and other changes due to the smog calibration the 70 did not have.
There are many reasons for the hesitation, but they can be tuned out easily.
The Q-Jet is something of a pain to get just right, but will run with anything once sorted out and will run 60-75k miles without problems-try that with a Holley!!!!!
 

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Doug Roe was an original Q-Jet engineer and his book is the best I have ever seen. I spent a week with Doug once and many hours on the phone with him.
The 72 got some jetting and other changes due to the smog calibration the 70 did not have.
There are many reasons for the hesitation, but they can be tuned out easily.
The Q-Jet is something of a pain to get just right, but will run with anything once sorted out and will run 60-75k miles without problems-try that with a Holley!!!!!
That's the kind of answer that I was hoping for - I've heard good things about Doug Roe's book and having a well-tuned Quadrajet.
 
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