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73-87 Chevy _ GMC Trucks => Performance => Topic started by: 76k104x4 on January 01, 2011, 09:48:31 pm

Title: Which carb
Post by: 76k104x4 on January 01, 2011, 09:48:31 pm
I want a new carb not sure if it should be Holley or Edelbrock spread or square bore or what. Now i have the factory intake and 4 bbl Qjet if i knew somebody that could id get it rebuilt and i have a Edelbrock performer intake i could put on too its for a square bore carb o and i got mechanical choke and dont want electric so what yall think i should get
Title: Re: Which carb
Post by: malibu795 on January 01, 2011, 09:50:14 pm
what size engine?

600cfm works pretty for most DD aplications
Title: Re: Which carb
Post by: 1980c10 on January 02, 2011, 01:03:27 am
spread bore is what you have with your q-jet, a spread bore carb will generally get you better mgp with typical driving.
A square bore carb will give you quicker throttle response.
btw you can buy new/rebuilt q-jet carbs. Why do you want a manual choke carb?
They are very easy to hook up if that is your concern.
What engine do you have and what are your goals for this truck?
Title: Re: Which carb
Post by: 76k104x4 on January 02, 2011, 01:11:24 am
i have a stock 350 except for headers and accel distributor i want manual choke because its what i have now i dont care about gas mileage at all i work in the oilfield job security ;D i use this truck as a DD but i also have a 07 GMC Z71 for going long distances and work i want throttle response,torque im goin to put a 4 inch lift and about some 35 inch tires on it not too big just right i think let me know if i left anything out thanks
Title: Re: Which carb
Post by: 1980c10 on January 02, 2011, 01:25:03 am
You'll get better throttle response out of a square bore carb because of its larger primary throttle plates. A spread bore carb has larger secondary throttle plates so once you're moving it'll be about the same on power assuming other variables are the same. Your q-jet probably flows about 750 cfm, but imo 650-750 is a good range. All you need to hook up an electric choke is a key switched 12v wire.
Title: Re: Which carb
Post by: 76k104x4 on January 02, 2011, 01:37:56 am
so edelbrock or holley i know yall got some opinions
Title: Re: Which carb
Post by: fitz on January 02, 2011, 07:25:45 am
For a daily driver/mild small block I think a Edelbrock 600 is the way to go.
Bolt it on, follow the instructions to adjust the idle mixture screws, and your done.
I've run many of these carbs on different small block powered vehicles over the years and was always happy with them.
Title: Re: Which carb
Post by: TandocTools on January 02, 2011, 07:35:45 am
I'm really liking the Edelbrock Thunder AVS 650 CFM I put on my C15!  Very good response right out of the box and in the Spring I'll buy their tuning kit and dial it in even more.
Title: Re: Which carb
Post by: malibu795 on January 02, 2011, 09:09:20 am
i got the performer 600

IMO erdelbrock is more setup for DD then holey is due how they are designed.
Title: Re: Which carb
Post by: ohio hab on January 02, 2011, 09:31:00 am
Holley 600, Electric Choke.
Title: Re: Which carb
Post by: three8six on January 02, 2011, 09:38:03 am
Holley would be my preferred carburetor. I have an edelbrock sitting on the shelf now for a reason.
Title: Re: Which carb
Post by: 1980c10 on January 02, 2011, 09:50:34 am
If this is an engine that you may do more modifications to; I would go with a 750 cfm, my preference is  holley after a q-jet but they all work, the tune is probably more important. Most people prefer carbs they have experience with or have seen work well. For a 4x4 I have heard of poor preference due to running the truck at steep angles for either a holley or edelbrock although I forget which was better. maybe someone here has heard about this?
Title: Re: Which carb
Post by: Captkaos on January 02, 2011, 01:20:06 pm
For a stock app, a 750 holley is WAY to big even if you plan to upgrade later.
a Q-jet CAN flow 750 but it operates on Vacuum, it will only draw in what it can pull in.

I would never run a Holley on a 4x4 due to float design, but if it is going to be flat roads shouldn't be a problem.

Title: Re: Which carb
Post by: 1980c10 on January 02, 2011, 01:57:25 pm
For a stock app, a 750 holley is WAY to big even if you plan to upgrade later.
a Q-jet CAN flow 750 but it operates on Vacuum, it will only draw in what it can pull in.

I would never run a Holley on a 4x4 due to float design, but if it is going to be flat roads shouldn't be a problem.


thanks capt. it was the holley float design I have heard of giving problems.
Title: Re: Which carb
Post by: bake74 on January 05, 2011, 10:59:03 pm
     A edelbrock 1605 is a 600 cfm with a manual choke.  I just rebuilt the one on my truck, they are easy.  The PO put it on for some reason, I am going to change it back to a q-jet when I find one in the wrecking yard.  The edelbrock is very easy to work on and tune.
Title: Re: Which carb
Post by: Grim 82 on January 05, 2011, 11:44:26 pm
In regards to the Holley float level, I experienced it just the other day when the motor quit when I was climbing a snowpile, which was much less of an angle than what I have previously climbed with an Edelbrock 1406 equipped. I have run a brand new Edelbrock 600, a brand new Holley 600 (which was tuned and jetted for my motor), and I have found that both of them perform about equal to a half worn out q-jet with a leaky base gasket. Your mileage may vary.

It seems like every thread about carbs involves somebody that wants to retire a q-jet (which I have done) and replace it with a shiny new carb. The original q-jet lasts for 30 years and then when it hiccups people say it's a piece of junk and get the shiny new one. And then get another one in 2 years, and another. Not picking on the original poster, or trying to start WW3, just showing up to the opinion party...

This guy will rebuild your q-jet: http://www.cliffshighperformance.com/

This guy will sell you a new one that works: http://www.smicarburetor.com/
Title: Re: Which carb
Post by: 1980c10 on January 06, 2011, 06:12:58 am
This guy will rebuild your q-jet: http://www.cliffshighperformance.com/
Tried cliffs a couple of weeks ago and they said it couldn't be done before august

I just had mine rebuilt by this guy
http://www.bigsperformance.com/ (http://www.bigsperformance.com/)
Haven't tried it yet, but his reputation locally is very good but on the expensive side.
He rebuilt mine in less than a day, repainted it two tone cast iron gray and aluminum, re-jetted and modified and set up for my motor. He test runs them on an engine in his shop and it is adjusted and ready to run. Once it is in my truck I will bring it in to his shop for fine tuning. My price was 220.00 I thought it was a deal, maybe it was since I am local.
Title: Re: Which carb
Post by: beastie_3 on January 06, 2011, 02:40:36 pm
Over 8 months to get a carb rebuilt? wow.
Title: Re: Which carb
Post by: jackjeckel757 on January 06, 2011, 03:42:10 pm
I say Edelbrock for smoothness & good mpg, but Holley for performance & power.
Title: Re: Which carb
Post by: 1980c10 on January 06, 2011, 06:43:37 pm
Over 8 months to get a carb rebuilt? wow.

back log of work I guess.
Title: Re: Which carb
Post by: Jim Rockford on January 11, 2011, 07:56:53 am
Been racing and driving chevies for years and you can not beat a good qjet for power and economy. Edelbrocks and holleys are just a waste .
Title: Re: Which carb
Post by: ToddN on January 11, 2011, 05:31:52 pm
True story.  I was sick and tired of my 1406.  I had a chevy delivery van sitting out in the yard that was there before we bought the house.  The last sticker on the van was 1991.  I took the Qjet off and replaced the choke coil with an electric one and also the choke pull off.  I did absolutley nothing to the guts in the Qjet except spray a can of carb cleaner on it.  I bolted it on, it fired up and I've had no problems.  And the performance is noticeably better with a couple more mpgs to boot.
Title: Re: Which carb
Post by: Jim Rockford on January 13, 2011, 09:32:47 am
Yep my last 85 GMC 1/2 ton I installed a tbi 350 from a old chevy van, and installed a 87 up aluminum 4brl manifold and pulled a qjet from a junkyard 4.3 pickup that was a cash for clunkers and it ran almost prefect.
http://www.youtube.com/watch?v=nG1kGrGx2Es&feature=mfu_in_order&list=UL