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Discussion Starter · #1 ·
Hi Everyone,

My engine guy told me I need a new carburetor. Right now I have a Holley, I am not sure which kind of Holley but I think its just a simple basic carburetor. My engine has around 336 HP, brand new Chevy Crate Motor - Small Block Engine. He told me to get the Edelbrock 1806 - Edelbrock Thunder Series AVS Carburetor:
http://www.summitracing.com/parts/EDL-1806/

But I have been researching around reading and I am confused on what to get....holley carb.....carter....quad jets.....rochester....edelbrock???

Here some picture of my engine now:

1973 Corvette Stingray Engine by 1973 Corvette Stingray, on Flickr


1973 Corvette Stingray est 334 HP by 1973 Corvette Stingray, on Flickr


Holley Carburetor 1 by 1973 Corvette Stingray, on Flickr


Holley Carburetor 2 by 1973 Corvette Stingray, on Flickr


Holley Carburetor 3 by 1973 Corvette Stingray, on Flickr


Holley Carburetor 4 by 1973 Corvette Stingray, on Flickr


Holley Carburetor 5 by 1973 Corvette Stingray, on Flickr


Holley Carburetor 6 by 1973 Corvette Stingray, on Flickr


Holley Carburetor 7 by 1973 Corvette Stingray, on Flickr

Here is the Edelbrock 1806 - Edelbrock Thunder Series AVS
http://www.jegs.com/i/Edelbrock/350/1806/10002/-1
Carburetors he told me to get so he can install it:

Edelbrock Carburetor 1806 by 1973 Corvette Stingray, on Flickr

Edelbrock Carburetor Thunder Series by 1973 Corvette Stingray, on Flickr

Edelbrock Carburetor 1806 by 1973 Corvette Stingray, on Flickr

Edelbrock Carburetor 1806 AVS by 1973 Corvette Stingray, on Flickr

Once again thank you for all of your help! And let me know
 

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How does your car perform now with the current carb? I have a guy that tuned my Holley and it's spot on. Mine is a 650 DP and it runs its ass off. I'll give you the guys number and let you talk with him:thumbsup: He lives in Alabama by the way.
 

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I just sent you a PM with the guys number. If you decided to get him to tune it for you drain all the gas and let it air out or you can't send it. I had that problem with mine when I sent it. When I got it back I had to tighten the bowl bolts as they're left loose for the shipping process to ensure that no gas was in there durning shipping. Good luck:thumbsup:
 

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Demon went out on Feburary 18 of this year. A Demon is nothing more than a glorified over-priced Holley. The only difference between a Barry Grant and Holley is the fuel bowls as everything else interchanges on the two.
 

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why does your mechanic think you need a new carb?
since that is a new engine, I wouldnt think the carb would go south that quick. what kinda problems were you having to make you take it in?
 

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Discussion Starter · #11 ·
why does your mechanic think you need a new carb?
since that is a new engine, I wouldnt think the carb would go south that quick. what kinda problems were you having to make you take it in?
All of you, thanks for your input. As you already know this is my first classic car, before this car I had a brand new C6. Please make it easy for me to understand :cheers:

He said the carb is probably not the right fit for this engine (too small too weak), he wants to improve the car overall. He said the one I have is basically not correct. The issues with the Vette is this:

- Leaks Fluid (possibly fuel)
- Horrible Gas Mileage (gas runs out too frequently)
- Car Has Trouble Starting
- Fuel odor in the garage (I am not sure if thats normal???)

Keep in mind everyone....he tinkered with the carb, and now it starts better, and I think he fixed the gas leak...all he did is mess with the carb....tighten and loosen screws...

He said its fine now, but he wants to make the car better, more improved, easier for me to drive and improve performance.....Overall really make it better....keep in mind, he is not going to sell me the parts....he said I can shop online and buy the carb myself and get the best deal. But he is recommending the Edelbrock 1806 - Edelbrock Thunder Series AVS Carburetor - 650 cfm electric choke.

Let me know, thank you
 

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Carburetors are more than CFM rating. The carb on your car is what holley builds for people with totally stock engines. So it's calibrated to run fairly lean. Calibration is more than jetting too. It's boosters and air bleeds and a lot of stuff that can be hard to grasp, but affects fuel air mixture at all throttle positions. You can change all of it with enough time and money, but really it's best to start with a correctly targeted carb.

The thunder carb, in addition to being slightly larger, is performance calibrated and will make more power at all throttle positions. It's better suited to your application. They're also quite reliable. Don't think you'd regret the purchase.

They also have gassy hot starts, not much you can do about it.

good luck
 

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Discussion Starter · #13 ·
Looks like I am going to get the thunder series...I think its a good fit for me.....thanks for your help.
 

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I love the edelbrock series of carbs they are great no messing carbs that do a general good job. But you wont see them on many real race for money cars.

I just swapped out a holley 650 double pumper for a street avenger 770 with vac secondarys. Night and day dif during transition. I am certain that I could have spent many hours tuning the 650 dp to transition properly during the summer but then would have had to retune for winter.

Air valve and vacuum operated sec. carbs dont generally suffer from seasonal issues air density issue etc..

Its a huge myth that you have to feel the secondary open up, it should be a smooth transition. Many guys tune AV/Vac sec. carbs for that feel and all they are doing is creating a drop in power on the dyno and drop HP until the engine and carb sync up again.

On a mechanical sec. system fine tuning adjustments have to be very precise. On an AV/Vac. system it relys on the intake pulse and air density to create the circuit that opens the secondary or air valve.

Rochester carbs are mechanical secondarys metered by the spring loaded valve on top and a power enrichment system.
Rochesters, perfectly tuned, are awesome for the street. The problem is it take lots of time and tuning to do it. Rochester carbs were mass produced carbs for 305 to 455 using the same cfm rating but tighter spring pressure on the air valve and jetting differences.

CFM calculators are generally hog wash. A properly jetted 750-850 will run perfectly and produce more HP then a 650 tuned correctly. It just depends on if its a mechanical or vacuum operated carb.

A 350 will always make more power with a larger carb. We have air pumps, the more air there is to be had the better they run. Its the type of power you want and when you want to make it.

A mechanical secondary 600 or 650, tuned properly, will deliver the type of all around driving you need. But it takes tuning and time.

A 750 or 850 AV/Vac operated willl fit the need too, and be much easier to use and you will spend less time and money tuning. It will also make more power on the top end when needed.


regardless of all the stuff said above, an AV/Vac operated carb will drop and run on a motor much easier and faster then a mechanical sec. carb like a holley.
 

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before I choose a carb I would need to know:

Bottom end is fresh and standard
Cam size
head type and valve size and any information regarding head work
compression
Intake
What type of transmission
What type of gearing
What type of stall converter
What type of driving you do
What kind of weather you generally have, air density/temperature can wreak havoc on mechanical secondary carb and tuning.
idle rpm in gear.
 

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CFM calculators are generally hog wash. A properly jetted 750-850 will run perfectly and produce more HP then a 650 tuned correctly. It just depends on if its a mechanical or vacuum operated carb.


Thats all well and good but, don't flame me I'm trying to get my head around this:thumbsup:

won't the larger throats of the 750-850 decrease the velocity of the incoming charge and hurt the torque in the lower RPM, which is what is being posted above?

I'm sure it probabley would increase hp, but is that what we want for the street.

I would think a spreadbore vac secondary would be the answer.....size who knows:huh:



:cheers: Liam.
 

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No, because vac/av opens up using a vacuum signal from the motor and opens up accordingly.
Rochester carbs are huge, yet because it uses an air valve on top of the carb to regulate the air flow the engine never pulls what it can't handle. Same thing with any av or vacuum system.

To answer your question velocity is created by the motor and intake not the carb. The carb just makes sure that the air passing through it is stochiometrically correct at 14 to 1 given every variable is met and adjusted. This is why av/vac carbs have spring or weight loaded valves or vacuum sensing valves to regulate the opening.

Quadrajets rock! They combine fuel efficient primaries with big hp secondaries.

When an engine builder uses a carb to increase velocity or reduces inlet size, there are other issues he is trying to address.
You will NEVER see any hot rod gizmo that makes more power on the top end ever restrict air flow.
However inlet flow can be increased to make low end torque!

Carb talk gets nutty after a while. Small Intake runners, such as on the old sp2p intake made huge low end torque but lousy top end hp.

It's a crazy and sordid life a carb leads.


You hit the nail on the head. Drivability. Av/vac secondary carbs are "generally" more driver friendly and offer the best of all the worlds.





Thats all well and good but, don't flame me I'm trying to get my head around this:thumbsup:

won't the larger throats of the 750-850 decrease the velocity of the incoming charge and hurt the torque in the lower RPM, which is what is being posted above?

I'm sure it probabley would increase hp, but is that what we want for the street.

I would think a spreadbore vac secondary would be the answer.....size who knows:huh:



:cheers: Liam.
 

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CFM calculators are generally hog wash. A properly jetted 750-850 will run perfectly and produce more HP then a 650 tuned correctly.
Now that is hogwash!

A 350 will always make more power with a larger carb.
So why don't we just put a 1050 cfm Dominator on all 350 c.i. engines? Terribly flawed logic..

regardless of all the stuff said above, an AV/Vac operated carb will drop and run on a motor much easier and faster then a mechanical sec. carb like a holley.
You need to go to an actual drag strip and see what real racers/engine builders use.
I gotta hand it to ya...in a couple of short days you've learned a lot....http://www.digitalcorvettes.com/forums/showthread.php?t=151768
 

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Actually the statement about cfm calculators is fairly true. Most 350s will ET better with 750 carbs than 650 carbs. That's what I see at actual dragstrips and engines I've built.

FWIW smog era 305 trucks came with 850 qjets, not the smaller 750 version most think they are.

There is much trickery to be played making different sizes of carburetor work best for a given application.
 

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Actually the statement about cfm calculators is fairly true. Most 350s will ET better with 750 carbs than 650 carbs. That's what I see at actual dragstrips and engines I've built.

FWIW smog era 305 trucks came with 850 qjets, not the smaller 750 version most think they are.

There is much trickery to be played making different sizes of carburetor work best for a given application.
I agree with most carbs. (at the dragstrip) will have larger cfm. They more often than not, have very aggressive cams and a much higher red-line than most street-driven vehicles. They are not worried about part-throttle operation. So in this specific case, a slightly larger carb. will work. I bow to the real engineers (not internet keyboard warriors) at G.M. from the '60's...who played around with engines like L-72's L-88's and LS-6's. G.M. gave up on the Carter carburetors (later copied/refined by Edelbrock, which they sell today), because of their limited performance potential. Same goes for the Q-jet...the lower H.P. engines got the Q-jet, the higher-output engines got the Holley. Even the legendary L-88 (about 560 h.p.) only had an 850 cfm carb. Just food for thought.
 
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