Holley's science vs Edelbrock simplicity?

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My 390FE in my pickup liked the holley over the edelbrock and my 289 liked the edelbrock over the holley, both 600cfm carbs. 390 didnt like the 750cfm edelbrock for some reason. I let my engine decide.
 
Please elaborate on the secondary door
Thanks
A quick look.

How it works;

The air door is spring loaded to be closed. Depending on the amount of load you put on it by twisting the spring tighter or looser will determine when the air door will open.

The air doors opening can be delayed or quickened. The AFB can not easily be adjusted. The difference? If you step on the gas pedal hard to accelerate very quickly, on the engine can tip the AFB’s counter weighted air door open causing the fuel to drop out of suspension. The engine goes lean until the fuel can get into the cylinders to start making power again. On the AVS, the secondary air doors opening is delayed to a point where the engine can consume the added air flow.

Since there is no secondary pump shot of fuel, the engine will see only air from the AFB for a moment. On the AVS, the air door is above the secondary boosters. On opening, the air rushes over the door which directs the air over and into the boosters.

Because the door is delayed in opening, the resulting constant air flow past the boosters and getting fuel moving quicker to the cylinders ends up having a smoother transition and no bog.

IF you have a bog with the AVS carb when getting into the secondaries, the spring needs to be tightened up. As you probably know, it is done on the side of the carb as shown below.

AA79C085-CB11-4D31-B13D-D02097809DFD.jpeg


Below is a number of pictures showing various positions of the secondary air door as it opens up so you can see the boosters slowly being uncovered by the air door.

Directly above the boosters, a rectangle slot is cut out in the air door to allow some air to go into and down the booster to Siphon fuel out and get it flowing.

The OE AVS was slightly different in it had no secondary boosters under its secondary air door. Just two tubes with holes drilled into them at various points. The number of holes can vary but I have never seen less than three holes to distribute fuel.

FWIW, Carter rated there AVS carbs at 630 & 750 cfm.

Anything else? Just ask.


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One of these crack wizz keyboard punchers was just recommending $1,000 Holley carburetor on another thread.
It's possible!
Holley FR-80909RD 1350 CFM Gen 3 Ultra Dominator Carburetor- Factory Refurbished
You do realize what you're suggesting is about a $1, 200 Adventure? You're really recommend in for my combination that the best money spent would be $1, 200 on 2 Holley carburetors??



No one said to buy a 1k carb. I said I was looking at one. I still am. You may not see the value in it, but I do. I didn't bat an eye to drop 850 on my BLP BX4 so what's another 150?
 
You want the high point of carb science/development? Id have to say later Thermoquads. C'mon, they had an altitude compensator! Remember these were built for a very specific motor combination and there were over 1000 unique carter 4bbl part numbers, so they were really dialing these needle/jet combos in.
 
I have had a few Holleys, and never again. I am NOT saying they aren't good carbs, I just had a lot of trouble with them. I might just have had a few stinkers, but twice burned. As a side story, I paid big bucks for a set of Michelin tires several years ago. They were terrible. My car went from a nice smooth ride to riding like a lumber wagon. Although most people like them, I had one bad experience, and that was enough. So bottom line is that one or two bad experiences is enough to turn a person against something no matter how many others love the item.
 
I left my wallet decide lol..
My experience is limited, but the eddies i bolted on out of the box had satisfactory results.
Set idle mixture and drive.
I didnt really have much to do with the holleys until the last couple years,my problem is i dont like fiddling with things i know little about. Seeing as i dont own any it stands to reason.
The more i have to do with them, i learn that i need a little more patience,and my customers that run them need to learn-not to screw with it.
The couple customers that have them dont seem to understand carbs at all,both need edelbrocks.
I think carburetor tuning is very much becoming a lost specialty. Edelbrock makes it just too easy for someone willing to take just the slightest amount of time to learn how to adjust.
 
Holley.

Your title says all that need to be said.

Science vs simple, total bull shete....

I can pull a 4150-4160-4500 down in 3 minuets and have it re built in 10.

I dont like your choice in carbs but i cant fault you for running what you know.

Holley, quick fuel, pro form, custom carbs. Are all built on the 4150 platform. That should tell you all you need to know.

Hell, even the new "EFI carb" systems are built around the 4150 design.
 
Well sure they are because Holley changed over the years while Carter went out of biz. Carter had only one race carb, 4 models of the TQ. And that’s before they were put on production vehicles. They also had an aftermarket TQ suited for Chevy or Chrysler, egr and non egr versions.
That’s it.

Holley on the other hand started in with there racing efforts and never stopped. The OEM Holley is the only comparable model to the Carters.
 
My 390FE in my pickup liked the holley over the edelbrock and my 289 liked the edelbrock over the holley, both 600cfm carbs. 390 didnt like the 750cfm edelbrock for some reason. I let my engine decide.

Probably the best answer yet. LEt your engine decide. They'll tell you that's fo sho.
 
Honestly if it wasnt for fabo i wouldnt be touching a holley for any amount of money.
But a few members have given some good info on setting them up,at least to the point where im not totally lost.
There was a good holley guy around these parts, i used to send people to him, but he has retired. Well as far as i know. Hes driving a subaru...
 
A quick look.

How it works;

The air door is spring loaded to be closed. Depending on the amount of load you put on it by twisting the spring tighter or looser will determine when the air door will open.

The air doors opening can be delayed or quickened. The AFB can not easily be adjusted. The difference? If you step on the gas pedal hard to accelerate very quickly, on the engine can tip the AFB’s counter weighted air door open causing the fuel to drop out of suspension. The engine goes lean until the fuel can get into the cylinders to start making power again. On the AVS, the secondary air doors opening is delayed to a point where the engine can consume the added air flow.

Since there is no secondary pump shot of fuel, the engine will see only air from the AFB for a moment. On the AVS, the air door is above the secondary boosters. On opening, the air rushes over the door which directs the air over and into the boosters.

Because the door is delayed in opening, the resulting constant air flow past the boosters and getting fuel moving quicker to the cylinders ends up having a smoother transition and no bog.

IF you have a bog with the AVS carb when getting into the secondaries, the spring needs to be tightened up. As you probably know, it is done on the side of the carb as shown below.

View attachment 1715377508

Below is a number of pictures showing various positions of the secondary air door as it opens up so you can see the boosters slowly being uncovered by the air door.

Directly above the boosters, a rectangle slot is cut out in the air door to allow some air to go into and down the booster to Siphon fuel out and get it flowing.

The OE AVS was slightly different in it had no secondary boosters under its secondary air door. Just two tubes with holes drilled into them at various points. The number of holes can vary but I have never seen less than three holes to distribute fuel.

FWIW, Carter rated there AVS carbs at 630 & 750 cfm.

Anything else? Just ask.


View attachment 1715377509 View attachment 1715377510 View attachment 1715377511 View attachment 1715377512 View attachment 1715377513 View attachment 1715377514

I had no idea
Great info, keep it coming
 
There certainly is a lot of tuning choices with the Holley's. Jets, power valves and plugs, accelerator pumps, cams, and squirters, vacuum secondary springs, bowl vent extensions, and the list goes on.
More accessories than at a Harley dealer. Probably tuning overload for most guys. especially street car owners. Heck many have issues getting the throttle and kickdown hooked up properly. Why would they need a carb with a hundred different combinations. Most of us could care less if this adjustment or that modification gains us a couple hundreds at the strip. "KISS" Keep it Simple
 
Last edited:
I had no idea
Great info, keep it coming

Later AFB's had a velocity valve but was a weight driven opening. The universal models were heavy where OEM carbs were tailored closer. A 273 had a very light opening where a larger engine might have a heavier opening rate. The only way to modify the opening rate on these carbs was to drill the weights or add weight to the valve. The purpose of these valves and the better spring adjustable valves is the size of the carb can easily adapted to a large range of engine sizes and performance levels. No power valves, no sensitivity to cfm for a specific engine.
 
There certainly is a lot of tuning choices with the Holley's. Jets, power valves and plugs, accelerator pumps, cams, and squirters, vacuum secondary springs, bowl vent extensions, and the list goes on.
More accessories than at a Harley dealer. Probably tuning overload for most guys. especially street car owners. Heck many have issues getting the throttle and kickdown hooked up properly. Why would they need a carb with a hundred different combinations. Most of us could care less if this adjustment or that modification gains us a couple hundreds at the strip. "KISS" Keep it Simple
In all fairness, this notion "eddies work out of the box and hollies don't" just isn't right. I've bought new holley carbs and never had a single one that didn't bolt on and run real good right out of the box. The only difference is, with the holley you can fine tune good in to great (that last tenth at the strip you were talk'n about). Just because you have more tuning options with a Holley doesn't mean they don't run good out of the box. However, I've had eddies that couldn't get rid of a bog out of the hole, and not enough tuning features so I had to ditch the carb... for a holley and tuned the bog out.
 
In all fairness, this notion "eddies work out of the box and hollies don't" just isn't right. I've bought new holley carbs and never had a single one that didn't bolt on and run real good right out of the box. The only difference is, with the holley you can fine tune good in to great (that last tenth at the strip you were talk'n about). Just because you have more tuning options with a Holley doesn't mean they don't run good out of the box. However, I've had eddies that couldn't get rid of a bog out of the hole, and not enough tuning features so I had to ditch the carb... for a holley and tuned the bog out.
I have two customers with ootb Holley's that work fine. And that's a good thing because beyond connecting fuel and a Direct Fit throttle cable they haven't a clue.
I teach them how to set the float and I show them how to set the idle and I show them how to adjust and set their choke and I show them how to adjust the air bleeds and for what reasons. I just tell them how the secondary spring works and how different Springs change how it works. I explained to them how the accelerator pump works and generally get that glazed look from them when I'm done explaining... it's information overload and they just want it to run good then pay me and drive off.... That amount of adjustability is wasted on most....
 
I have two customers with ootb Holley's that work fine. And that's a good thing because beyond connecting fuel and a Direct Fit throttle cable they haven't a clue.
I teach them how to set the float and I show them how to set the idle and I show them how to adjust and set their choke and I show them how to adjust the air bleeds and for what reasons. I just tell them how the secondary spring works and how different Springs change how it works. I explained to them how the accelerator pump works and generally get that glazed look from them when I'm done explaining... it's information overload and they just want it to run good then pay me and drive off.... That amount of adjustability is wasted on most....
Then just bolt it on and let them smile. Don't explain the rest.
 
There certainly is a lot of tuning choices with the Holley's. Jets, power valves and plugs, accelerator pumps, cams, and squirters, vacuum secondary springs, bowl vent extensions, and the list goes on.
More accessories than at a Harley dealer. Probably tuning overload for most guys. especially street car owners. Heck many have issues getting the throttle and kickdown hooked up properly. Why would they need a carb with a hundred different combinations. Most of us could care less if this adjustment or that modification gains us a couple hundreds at the strip. "KISS" Keep it Simple


It is really simple, if you want to learn it. It's not hard. You just have to break down the systems.

Reading this thread is revealing. There are some under the notion who think an certain engine brand runs better with a certain brand of carb. The carb is utterly ignorant of what engine it is bolted to. I've heard this theory since 1980. And it's just silly. The name on the valve cover and the name on the carb are not related.

The carb, any carb is just a pressure differential sensing device. In those terms, it's really basic and simple. High pressure always goes to low pressure. Venturi and Bernoulii work together. Both easily understood concepts.

To think a carb, any carb, with an essentially generic tune up out of the box is bolt on, is laughable. Are they close? Maybe. Good enough? Evidently. But mostly untrue.

The air fuel ratio meter has become the slide rule of engine tuning. Trying to tune by a number is just an effort or circular logic. Does your meter read the same as every other meter out there? Damn sure no. Is the ideal A/F ratio the same for every engine? Not by a long shot.

If your ignition is worth a tinkers damn, you may be able, with the correct tune, achieve a 15:1 A/F ratio at cruise. Most guys settle around 14. And that's not a sure 14. It may be 13.8 or 14.3 with a different meter.

To claim an out of the box tune up is perfect is naive at best, and foolish at worst. I've done more than enough dyno work to know it just isn't true. Settling for a tune is ok if that's all you want.

I'm a firm believer (for many years now) that all of these carbs are 100 MPG carbs. All of them. The Carter, Holley, TQ, Q-jet...all of them. Why they aren't is for another thread.
 
In all fairness, this notion "eddies work out of the box and hollies don't" just isn't right. I've bought new holley carbs and never had a single one that didn't bolt on and run real good right out of the box. The only difference is, with the holley you can fine tune good in to great (that last tenth at the strip you were talk'n about). Just because you have more tuning options with a Holley doesn't mean they don't run good out of the box. However, I've had eddies that couldn't get rid of a bog out of the hole, and not enough tuning features so I had to ditch the carb... for a holley and tuned the bog out.
This is absolutely 99% dead on balls accurate the truth.
And this is also where the above line of “Tuning overload “ comes in. The amount of tuning points in a Holley can fry the brain. When your used to dealing with a Holley, there’s no sweat involved. When your new or not so experienced, your brain melts with options.

I had no idea
Great info, keep it coming

What do you want to know?

Later AFB's had a velocity valve but was a weight driven opening. The universal models were heavy where OEM carbs were tailored closer. A 273 had a very light opening where a larger engine might have a heavier opening rate. The only way to modify the opening rate on these carbs was to drill the weights or add weight to the valve. The purpose of these valves and the better spring adjustable valves is the size of the carb can easily adapted to a large range of engine sizes and performance levels. No power valves, no sensitivity to cfm for a specific engine.

This reminds me of something;


The early AFB carbs were a little different than later years. One model that comes to mind was on a friends ‘67 - 440 in his land yacht. The small neck AFB had no secondary air door at all. It was also a small 600.

When I was a younger man. I had my ups and downs with the AFB. I always considered the Carter/Edelbrock carb a street and high performance carb. Not a race carb. Regular less of what other people have done with them, I found that a smaller carb, no matter the make, works a fair bit better on the street for an actual driver. (As most of know) This I have found very true of the AFB. Since the counter weighted door isn’t so easy to modify for its opening rate & timing. This is where I like the AVS (& the TQ) much better for that tunable secondary air door.
 
Bang on!

No matter the carb, some tuning is more than likely needed. Even if it runs GREAT! OOTB.

Now what was that definition of a carburetor again?

“A device designed to confuse and confound .....”

Yup! A description that is 100% accurate until you know better.

It is really simple, if you want to learn it. It's not hard. You just have to break down the systems.

Reading this thread is revealing. There are some under the notion who think an certain engine brand runs better with a certain brand of carb. The carb is utterly ignorant of what engine it is bolted to. I've heard this theory since 1980. And it's just silly. The name on the valve cover and the name on the carb are not related.

The carb, any carb is just a pressure differential sensing device. In those terms, it's really basic and simple. High pressure always goes to low pressure. Venturi and Bernoulii work together. Both easily understood concepts.

To think a carb, any carb, with an essentially generic tune up out of the box is bolt on, is laughable. Are they close? Maybe. Good enough? Evidently. But mostly untrue.

The air fuel ratio meter has become the slide rule of engine tuning. Trying to tune by a number is just an effort or circular logic. Does your meter read the same as every other meter out there? Damn sure no. Is the ideal A/F ratio the same for every engine? Not by a long shot.

If your ignition is worth a tinkers damn, you may be able, with the correct tune, achieve a 15:1 A/F ratio at cruise. Most guys settle around 14. And that's not a sure 14. It may be 13.8 or 14.3 with a different meter.

To claim an out of the box tune up is perfect is naive at best, and foolish at worst. I've done more than enough dyno work to know it just isn't true. Settling for a tune is ok if that's all you want.

I'm a firm believer (for many years now) that all of these carbs are 100 MPG carbs. All of them. The Carter, Holley, TQ, Q-jet...all of them. Why they aren't is for another thread.
 
This is absolutely 99% dead on balls accurate the truth.
And this is also where the above line of “Tuning overload “ comes in. The amount of tuning points in a Holley can fry the brain. When your used to dealing with a Holley, there’s no sweat involved. When your new or not so experienced, your brain melts with options.



What do you want to know?



This reminds me of something;


The early AFB carbs were a little different than later years. One model that comes to mind was on a friends ‘67 - 440 in his land yacht. The small neck AFB had no secondary air door at all. It was also a small 600.

When I was a younger man. I had my ups and downs with the AFB. I always considered the Carter/Edelbrock carb a street and high performance carb. Not a race carb. Regular less of what other people have done with them, I found that a smaller carb, no matter the make, works a fair bit better on the street for an actual driver. (As most of know) This I have found very true of the AFB. Since the counter weighted door isn’t so easy to modify for its opening rate & timing. This is where I like the AVS (& the TQ) much better for that tunable secondary air door.
"What do you want to know"
The winning lottery numbers would really help. LOL
 
No one said to buy a 1k carb. I said I was looking at one. I still am. You may not see the value in it, but I do. I didn't bat an eye to drop 850 on my BLP BX4 so what's another 150?
You yourself have recommended high dollar carbs often. The merit of there worth will vary upon application. With respect, I think some of the suggestions of such $1000 carbs were a misfire only due to the intended application at hand for the end user. This is not an insult, argument starter or a debatable thing. Just a point of view where I scratch my head and wonder. Why spend big on a carb a guy doesn’t understand how they work and ditch the cheaper carb and simpler carb that he understands and will work for the intended application on the street and sometimes strip.
 
Then just bolt it on and let them smile. Don't explain the rest.
LOL... Op, why the disagree?? you say your customers get mind boggled because you explain. You say all they want is the car to run good. So bolt it on and give them a good running car. If I get a prescription from the doctor, he don't explain all the ingredients, and I don't care. I want it to work, clear up the infection, or whatever. Sounds like this is how your customer wants it. So be it. Bolt it on and give them a good running car.
 
I am running an AVS 2 right now.
I spend more time trying to find those ******* little clips that just SPROINGED... off into oblivion on this Eddie than I would changing jets on a Holley !
Lol
 
I am running an AVS 2 right now.
I spend more time trying to find those ******* little clips that just SPROINGED... off into oblivion on this Eddie than I would changing jets on a Holley !
Lol
I like the idea behind the AVS2. How is it working for you?
 
Then just bolt it on and let them smile. Don't explain the rest.
Both those carburetors were already on the cars or trucks actually. I help people restore their classic vehicles and teaching them how to maintain them. I barely know enough about Holley's to be dangerous. All I can say is my experience with the general public and carburetors most don't know crap which means it's way easier on me when they have an Edelbrock.
Two weeks ago it was a 57 Chevy and the customer bought it with a 350 4 speed conversion. It had a new Edelbrock 1406. The choke is open and it's idling extremely high then I asked is that normal and he's like yeah it runs great doesn't it? Isn't it going a little fast? So I idle it down just a little bit and it dies? Again to start it back up and it dies....? I crank the idol back up and it runs. I open up the left air bleed and guess what it idles up pretty high. Bring the idle down, adjust the other side, keep bringing the idle down and so on till it was purring like a kitten. Very happy customer and an easy payday, thank you Edelbrock!
 
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