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Topic: quadrajet performance

in Forum: C3 Fuel, Emission Control, and Exhaust Systems


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quadrajet performance (1/10)
 10/22/10 9:19pm
rod7515Lifetime Member
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Red Lion, PA - USA

Vette(s):
1974 White 350 Corvette, TH400 Automatic 1972 Tangerine /Go Mango Convertible 383 Stroker, 2004r Automatic


Joined: 10/27/2006
Posts: 1182

I was wondering if there is anyone here that has upgraded the performance of their quadrajet or is it just easier to go to a holley or edelbrock? I get very good road driving ability with my quadrajet on my 74 350, and it also delivers great gas mileage but it doesnt respond as quick as I'd like it too the secondary vacuum is slow coming in. I know going to something else will effect fuel mileage but i want better response. I havent tried to make any changes with the quad yet. Was wondering if there are any websites that offer ideas and products?

Thanks
Rodney


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quadrajet performance (2/10)
 10/22/10 10:58pm
KDADDY79
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Dutchess County, NY - USA

Vette(s):
White '79 Corvette. It's a driver.


Joined: 8/27/2007
Posts: 2484

I'm not able to do a good rebuild on my own so I sent my Q-Jet out for a rebuild a few years ago.

Getting it rebuilt RIGHT meant all the difference in the world. Since then I can really feel the secondaries go to work.

I had mine rebuilt by http://www.thequadshop.net/  Great to deal with!

Stick with your Q-Jet! Thumbs Up
 
Kevin
KDADDY792010-10-22 20:00:41
quadrajet performance (3/10)
 10/23/10 5:32pm
Per4manceLifetime Member
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Morganville, NJ - USA

Vette(s):
1971 350 270 hp roadster millivanilli red, black interior, white rag top, white hard top, I've had it 18 years and intend on giving it to my son for his 25th birthday(another 18 years from now)


Joined: 1/25/2009
Posts: 92

Adjust the door on the secondaries for lighter spring tension, and the secondaries will open faster. The adjustment is under the secondary door rod on the top of the carb.if you are not sure about the screw look on line and you can get a look at which one to turn......... Bill
quadrajet performance (4/10)
 10/25/10 11:38am
VetteSpecialties
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Mounds View, MN - USA

Vette(s):
70 LT1 coupe, 69 350 HP coupe, 69 390HP 427 coupe, 71 LS5 convert, 85 coupe, 93 coupe


Joined: 5/24/2007
Posts: 1031

Remember the secondaries are supposed to come in as the engine can support the additional airflow.  It is not necessarily a good thing to make them open faster.  Overall engine condition and tune must first be addressed, then carb adjustments checked.  Then worry about a rebuild.

Larry
quadrajet performance (5/10)
 10/25/10 12:06pm
dskopp
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Oak Creek, WI - USA

Vette(s):
1981 Great White Shark. Red Interior, 350/190hp. PS, PB (SS), A/C CC, T-Tops, Going to remain as Stock as possible. Served three years in Active Duty Army, then Retired Air Force after 34 years! Badger State Vetts Car Club. 175,000 Original miles!!


Joined: 5/21/2008
Posts: 1958

Rodney, send me a PM with your email address and I can send you some info on the Q-Jet that may help you !!
Dan


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quadrajet performance (6/10)
 10/26/10 2:56pm
yostusota
Former Member

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York, PA - USA

Vette(s):
1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top


Joined: 5/18/2010
Posts: 1518

Hey Rodney if you are free this weekend maybe we can get together and tweak the secondary or the accelerator pump..I am not going anywhere this weekend so it would work for me to tune it a little if need be..it would be fun to do before CFC.
Rich

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quadrajet performance (7/10)
 10/26/10 10:10pm
rod7515Lifetime Member
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Red Lion, PA - USA

Vette(s):
1974 White 350 Corvette, TH400 Automatic 1972 Tangerine /Go Mango Convertible 383 Stroker, 2004r Automatic


Joined: 10/27/2006
Posts: 1182

Rich, Appreciate the offer but this weekend is the guys golf trip. We leave Thursday for 4 days off golf food and rest! The first weekend I have free is the weekend of the 11th. Maybe then we can give it a shot if your free. Thanks
Rodney


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quadrajet performance (8/10)
 10/27/10 12:03pm
yostusota
Former Member

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York, PA - USA

Vette(s):
1969 daytona conv. all original 350 350 380 4 sp w/air..and hard top


Joined: 5/18/2010
Posts: 1518

Hey Rodney that sounds great on the 11 th..would be fun.
Rich
 


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quadrajet performance (9/10)
 10/28/10 12:04am
lbbounder
Standard Member
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Florence, KY - USA

Vette(s):
1977 Coupe; yellow, 4 speed, one option car with original engine


Joined: 9/9/2007
Posts: 143

OK, so when I mash the accelerator there is a stumble... and fuel mileage seems to have decreased. You say this guy is good ay rebuilding Q-jets. ...been contemplating switching to Holley.

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1996 Grand Sport
1984 coupe 
1974 coupe
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quadrajet performance (10/10)
 10/28/10 12:24am
rod7515Lifetime Member
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Red Lion, PA - USA

Vette(s):
1974 White 350 Corvette, TH400 Automatic 1972 Tangerine /Go Mango Convertible 383 Stroker, 2004r Automatic


Joined: 10/27/2006
Posts: 1182

Joe, Rebuilding the carb is not that hard of a job. These carbs are not that difficult to make them run good. I am looking to get more of a high performance response with mine and that is not the standard set up. The reason I would like to stay with the quadrajet is because when just driving out on the road the economy is better then anything I think you can get. You can certainly get rid of your stumble as long as you have a good carb to work with. And yes tuneup could also play a major part in the stumble as well. Good luck.
Rodney


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