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#1 |
Registered User
Join Date: Nov 2013
Location: Sherwod, Or
Posts: 77
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Quadrajet or Holly 650
This is on a '77 GMC C2500. Stock 4 speed, 4.11 Gear. I am not racing, just running on the street.
SO, initially I am having issues at full throttle. When running I can get trough second and third, but when I go into fourth and hit the gas my truck stutters and fails to speed up. If I gently push the gas it seems to keep up. Not that I floor it a lot, but I should be able to punch it. I know very little about the Qjet's so I am starting very low there. I am going to pull the truck in for the winter and go through both gas tanks, replace lines, replace the mechanical fuel pump, so this MAY actually solve my issue. I have the option of getting and rebuilding a Holly 650 to put on the stock intake. Will this even be worth it? Will there be a performance (MPG?) increase doing this? I hope there are not a hundred other threads on this ( I tried searching and didn't find any). I would love your input on this! |
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#2 |
Registered User
Join Date: Dec 2012
Location: Preble county ohio
Posts: 1,914
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Re: Quadrajet or Holly 650
On a stockish engine you can't go wrong with a quadrajet! Get yourself a book and rebuild it right, I've had holley carbs and edelbrock carbs on my truck and I keep coming back to the quadrajet, decent power and the best milage this side of fuel injection
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"DON'T TOUCH THE TRIM!!"-Early Kyler |
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#3 |
Registered User
Join Date: Nov 2013
Location: Sherwod, Or
Posts: 77
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Re: Quadrajet or Holly 650
Thank's for the input! When I first got the truck a few years ago I had a tune up done, but I was only getting a little over 6mpg!! I think I have a delivery issue though. That's why I am going through and replacing everything. Not sure what MPG I should expect with the 454, but that seemed low. I will find a rebuild kit for the Qjet and stick with that if that is the best thing for now.
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#4 |
Registered User
Join Date: Nov 2013
Location: Sherwod, Or
Posts: 77
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Re: Quadrajet or Holly 650
Upon research......I guess that's on the high side of what I should expect....SMH...
Anyone need a 454.... ![]() |
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#5 |
Registered User
Join Date: Dec 2012
Location: Preble county ohio
Posts: 1,914
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Re: Quadrajet or Holly 650
I rebuilt mine with a small bump in compression, a small cam (comp he260) headers and a performer intake, with a fresh quadrajet, 10 around town, 12 on the open road, no overdrive, 3.73 gears, and that is in a crew cab dually, when I got the truck it was stock with an edelbrock 750 on it and it got 9
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"DON'T TOUCH THE TRIM!!"-Early Kyler |
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#6 |
Registered User
Join Date: Jun 2014
Location: CO
Posts: 738
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Re: Quadrajet or Holly 650
I would go with the Holley if it were mine. The holley is easier to adjust float level and idle mixture screws on the side. The q-jet has idle screws in the front and if you get junk in carb you have to take half the carb apart to clear. I have a q-jet on Trans Am and Truck, it took me a lot of tinkering to get the q-jet on TA to start with just a flick of the key. The q-jet on truck is fighting me though and needs some more fine tuning, I just rebuilt q-jet so trying to stick with it for now. I might switch to a Holley on truck with vacuum secondaries and it should get about the same gas mileage as q-jet. In the end both carbs are good but q-jets a bit more fickle IMO.
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79 Chevy 2wd BIG10 350 TH400 |
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#7 | |
Registered User
Join Date: Aug 2009
Location: Bowser
Posts: 13,603
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Re: Quadrajet or Holly 650
Quote:
What's your timing like truckin? |
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Tags |
454, c2500, holly, quadrajet |
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