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I want Q-Jet unstead of Edelbrock

fine69

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I want to replace Edelbrock AVS with Q-Jet

Well I decided to replace the Edelbrock Thunder Series AVS 650 cfm carb. I've never been too thrilled with it. First, the primaries appear way too big for street driving. I like the idea of Q-jet's small primaries and large secondaries to be activated when needed.

Can't seem to get the fuel mixture just right, and with fuel back pressure issues, I do not want to use an electric fuel pump. I want to replace the carb with a standard Rochester Qudrajet carburetor. I also want to replace the braided steel lines with the original steel stock fuel line system --- the one that has the filter and the overflow "return" fuel lines.

I should also replace the Edelbrock fuel pump with the stock one, no? I don't think the fuel lines are the same.

I contacted someone who can rebuilt a Q-jet with the electric choke correct for my '69. Without a core, he'll charge me $275, plus shipping. He needed to know some specs from my car such as headers, and camshaft.

My engine has the Edelbrock Performer intake manifold, and Edelbrock Aluminum Performer RPM 64cc heads. I was planning to use the Performer manifold, but still have the stock GM intake manifold - just not sure how this setup will work with the aluminum heads.

Will the Q-jet install and perform well with this setup, or do I need to use the old GM manifold?? Which should work the best? Any comments are appreciated.

Ralph:W
 

Evolution1980

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I believe a factory QJet will fit just fine on your current Edelbrock intake. As long as you have no clearance issues, I'd stick with the Edelbrock. I believe the OEM GM was a bit lower profile to avoid clearance issues. Also, I would think with the Edelbrock being newer technology-wise, you'll get better slightly better performance from it.

$275 was to rebuild/tune your QJet or just to get you a rebuilt one? For just a rebuild, that sounds expensive. But then again, I don't know what a rebuild goes for. As for tuning it, he'll only be able to get you close. You won't really know if it's performing to it's fullest until you can get your car on a dyno and check the A/F. It's how I ended up getting mine tuned. Take a couple different rods & jets and replace 'em between pulls. (Well, the jets not so much as the rods).
BTW, Edelbrock makes all the correct replacement rods for the QJets now.
 
T

tonyvdb

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I've used both types of carbs with no problems with either one. I had a 76 with a 400 sb with an edelbrock 600cfm carb and it ran perfect right out of the box.
When I brought the 70 it had a holley but came with the orginal qjet and manifold which I put on. It needed a little adjustment but it also runs great. Can't really compare as they were on different engines, but I can say that they will both do a good job.
 

Sensei

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Will the Q-jet install and perform well with this setup, or do I need to use the old GM manifold?? Which should work the best? Any comments are appreciated.

Ralph:W

As long as it is the spread bore performer intake (2100?), the Q-jet should work great. God bless, Sensei
 

problemenko

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1979 White/Black
Check out Sean Murphy Induction in CA. He produces great QJets based on your requirements for around 300 delivered. Just Google his web site. I have one on my car and it works great!
 

fine69

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$275 was to rebuild/tune your QJet or just to get you a rebuilt one? ....BTW, Edelbrock makes all the correct replacement rods for the QJets now.

This would be to actually build one based on the specs of my engine setup. In order to utilize an electric choke (which I requested), he said he would need to use Quadrajet from a 1979 or 1980. He said it should bolt on and function perfectly.

He also gave me an updated quote. He'll charge me $245 as long as I turn in a core Q-jet. Does that sound reasonable?
 

fine69

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As long as it is the spread bore performer intake (2100?), the Q-jet should work great. God bless, Sensei

Arigato, Cris san!
 

fine69

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Check out Sean Murphy Induction in CA. He produces great QJets based on your requirements for around 300 delivered. Just Google his web site. I have one on my car and it works great!

I'll definately contact them. Their site lists some good testimonials.

Thanks.
 

Evolution1980

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In order to utilize an electric choke (which I requested), he said he would need to use Quadrajet from a 1979 or 1980. He said it should bolt on and function perfectly.
Hmmm..I don't think my car ever had an electric choke. ...maybe it did. Hell, maybe it still does, but I don't think so.;shrug
Even my QJet isn't stock anymore... :L
Ah well...He probably knows what he's talking about more than I do! :cool
 
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Since your current carburetor is Edelbrock, I would bet you have a square bore intake. That won't fit with a spread bore quadrajet. Maybe a call to Edelbrock will help you get it tuned with just a simple rod change. My Edelbrock 600 ran perfect right out of the box. My 76 had a quadrajet with some kind of heat riser thing to the manifold that controlled the choke not an electric choke. I would suspect older models also had that heat riser type thing also. My old carburetor is for sale if you can use it.AS far as performance, the Edelbrock manifolds will give you better performance than what you had as stock, even if you go back to the Quadrajet carb. The beauty of the new manifolds is the looks and performance for less than $200.
 

Sensei

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Most performer manifolds are for spread bore. The square bore carbs fit with an adapter plate. God bless, Sensei
 

Crimson Thunder

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Orange Park FL USA
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Most Performers are drilled for both square and spread bore.I'm running a Holley Street Avenger carb on an Edelbrock Performer intake with no problems.
 

fine69

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Summit Racing Remanufactured, Q-Jet, 750 cfm

Summit Racing sells remanufactured Q-Jet 750 cfm carburetors. The cost is $314.95 and has a "divorced choke"... What the heck is a divorced choke? :confused

Here's the item: http://store.summitracing.com/partdetail.asp?autofilter=1&part=SUM-210210&N=700+0&autoview=sku

Does anyone know if these are any good?

As you know, I'm also thinking about a rebuilt one (1979-80) that has an electric choke - not sure if that one is 750 cfm.

I'm probably making this more difficult than needed... sooooo confused, jeez.;shrug

Thanks everybody!

Ralph
 
B

bmotojoe

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I believe the divorced choke is the older style setup, when GM stopped using it I am not sure. The thermostatic spring fits inside the intake manifold and a linkage connects between that and the choke plate linkage of the carburetor.
Brian
 

fine69

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'69 Convertible Vette; '72 Z28 Camaro Rally Sport
I believe the divorced choke is the older style setup, when GM stopped using it I am not sure. The thermostatic spring fits inside the intake manifold and a linkage connects between that and the choke plate linkage of the carburetor.
Brian

Hey Brian,

Thanks for the reply... yeah, now I remember that type of choke. The electric choke is much better choice - for me anyway.

Ralph
 

Lucy64

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I had a new Edelbrock 750 on my car and had nothing but problems. It ran rich and never could get it right. I took it to an old guy that had gone to the old Carter school and he knew that carb inside and out. He worked on it and it still was not right. I pulled it off and bolted a new Holley Street Avenger 770 on my Edelbrock Performer manifold. All I had to do was a minor float adjustment and it runs great. I totally swear by Holley.
 

Evolution1980

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As you know, I'm also thinking about a rebuilt one (1979-80) that has an electric choke - not sure if that one is 750 cfm.
Ralph, it is from a Corvette, then yes, it's a 750 cfm.
 

fine69

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Ralph, it is from a Corvette, then yes, it's a 750 cfm.

Thanks Andre. I went ahead put an order in for the custom-tuned electric choke q-jet. The guy gave me a discount... the carb, pigtail, and shipping for $250. Hopefully he'll get it done by the end of the week! I'm really looking forward to getting this installed.
 

Jack

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Ralph:
I saw this thread just today.

Did you order the carb from Lars in CO? Lars has a great rep w/qjets & tach drive distributors ... Lars' email: V8fastcars(AT)msn(DOT)com
 
A

Autom8r

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A properly set up Q-Jet is the very best street carb you can have on your plastic hot-rod. GM had it engineered for economy and street performance by a group of high-dollar and talented engineers. At cruising speed the air-fuel mix is very efficiently atomized by the presure drop and airspeed increase thru the small primaries, then at WOT the gigantic secondaries open up for TONS of flow. The standard Q-Jets are 750 CFM, and opened up to 800 CFM on the L-82s (and 500 CI Caddies). You can differentiate them by sliding a 3/16" rod between the primary air horn and the bore, if it fits, it's an 800 CFM carb.

One of the main flaws in these dinosaurs is that there are no bushings in the bare aluminum body at the throttle plate rods. If there is any slop between the rods and the worn body bores, it needs to get some bushings on a proper rebuild. I bit the bullet and had mine rebuilt by Jim McGowan at the Quad Shop in Rockford, IL. The guy taught me more than I'll ever need to know aout Q-Jets. He ain't cheap and mine took forever to get back, but it was perfect when I did get it back.

Dave
 

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