Holly-vs-Edelbrock

Just thought I would throw this one out there for discussion. Which is the better carb? Holley, Edebrock, Barry Grants or Quadrajets. Based on stats such as power, mileage, ease of tuning, durability, streetability etc. I know there is a price difference but not interested in that. Hope to hear a lively debate. Happy hot rodding everyone. Steve

Just thought I would throw this one out there for discussion. Which is the better carb? Holley, Edebrock, Barry Grants or Quadrajets. Based on stats such as power, mileage, ease of tuning, durability, streetability etc. I know there is a price difference but not interested in that. Hope to hear a lively debate. Happy hot rodding everyone. Steve
Wow, one can write a book on this topic.
I have never used Grants, (I'll look it up) but as for the others.

Holly 4bbl carbs come in several variations. The full-race Dominator series has no equal, but is generally a race-only piece.
Other Holly carbs are generally an older design that the others, as the basic layout dates from late 1954, but has been highly modified since then. Their advantage is that there are many many different sizes (measuresd in CFM, from 390 to 850) and designs, for different applications.
Square-bore, spread bore, vacuum secondary, mechanical secondary, double accelerator pumps etc are all features designed to tailor their use from a plain, bone stock engine to a full-race application.
Their modualr design allows for such a different range.
Therefore, its tough to discuss Holleys overall, as there is such a wide range of applications.
Generally, though, they are best for performance applications where their tuneability is helpful. They function well with long-duration camshafts that don't provide much vaccuum signal, something the others, especially Quadrajets are not so good at.

Their disadvantage is that they are relatively unsophisticated in terms of adjusting the mixture enrichment in response to vacuum and airflow changes. They rely on 2 or 3 stage 'power valves for enrichment. Therefore, they often run a bit too rich or lean at various levels of air flow and throttle opening.
They are also quite complicated to tune. I have come across many people who curse Holleys simply because they do not know how to set one up properly, or they have selected the wrong model (usually by choosing one with more CFM than is necessary, or a mechanical seconday system instead of a vacuum method)

Also the Holley often can't get quite the same gas mileage of the other two, when all are set up properly.

Quadrajets are a more sophisticated carb, and use a needle and jet method of metering fuel for the secondary barrels. This is great because it provides more precise fuel metering (when set up properly.) The venturi design on the primary side is also more sophisticated than a Holley design and provides accurate metering and a finer atomization of fuel than a Holley. However, they are more sensitive to a lack of a strong vacuum signal and run more poorly that a Holley if there is a long-duration camshaft. Also, tuning parts are more difficult to come by, the small primary and huge secondaries give the carb a bit of a all-or-nothing feel whan driving and the float bowl is a bit too small. Therefore, they are best for a stock or near stock engine.

Edelbrocks are based on the Carter design from the 60's, but have been updated. They provide the sophistication of the Q-jet with something approaching the tunability of a Holley.

So, neither is best, it depends on the application. I would say for all round performance use, the Edelbrock is best.

The Holley is best with wild camshafts, big blowers etc, or when gas mileage is not a big concern AND if the owner or mechanic knows how to set it up properly.

If one has a stock or near-stock GM car with a Q-jet, keep it and tune it right; it will be just fine.

Finally, what about one of my personal favourites the Autolite (Ford) 4bbl? These things have an excellent design, are compact, simple and extremely efficient. Tuning can be a challange, especially rejetting, but if one has a stock or mildly modified Ford or AMC product with one of these, they are an excellent alternative to an aftermarket carb.

Also, lots of people have had good luck with Mopar Thermo-Quad carbs, too.

Am I biased to Edelbrock carbs? No. So what do I drive with? My various cars have a Holley 390, a Holley 750 (both square bores) a Holly 650 spread bore, one Q-Jet and two Autolite 4500 carbs. Not an Edlebrock in sight, although I have driven with a Carter carb in the past.

If your know how to tune a carb a BG Demon is the way to go...optimum performance. Edeljunck for no nothing. Hollies not much better.

Well, contrary soxs post, i think the best one would be a holley. I have had nothing but good things from them same with my dad and same with my freinds uncle. They come out of the box ready to drop on, the test run i did on the novas new 396 was with a barry grant, i didnt do so well but im not going to hold that against it since it was tuned for a small block 383. Just my :2cents: .

Thanks to MagicRat for an excellent description of the highs and lows of each design. And I agree with the majority of what he says. I disagree that the Edelbrock carbs are better than the old Carters they are based on. In truth, we've seen a BUNCH of tuning problems with the E-carbs. You can get them to idle and transit well, and they won't make the high-end. You can get them to make the high-end, then they stumble at low speeds. Several carb guys report the same problems. The REAL Carters are still available, and quite good.
For horsepower? Holley. No contest. FYI, at the Indy Nats in September, I had occasion to look at the BG pro stock. Holleys... If those Demons are better than Holley, and not just the cheap knock-off they appear to be, why are they NOT on his race car?
The Q-Jet is the most versatile, and IMO, the better choice for a driver. All the jokes like "Quadra-junk" or "Quadra-flood" are aimed at the wrong source. If you rebuild a Q-Jet with a fibre float, and don't replace it, it WILL flood... The throttle shafts also do wear out. They can be repaired relatively easily. The lack of fuel in the bowl is the biggest drawback. A little bigger needle/seat and more fuel pressure can help.
But if you're looking for the best combination of fuel economy AND performance, Q-Jet is where it's at.

Ahhhhhhhhh. Information overload in process here. LOL. Thanks for that thorough replay to my query. I was interested because I recently put an Edelbrock 600cfm on my mildly build 302 and have been having a bitch of a time tuning it. As someone said it idles great but chugs with acceleration. I suppose it could be the fuel pump or something but it ran decent until I started messing with the settings on the Edelbrock. Was hoping that the Holleys were easier to tune but apparently they all have their good points and bad points. The Barry Grants are new but have heard some good things about them and seen them in use on some of the "tuner" shows on Discovery and TLC. I used to be a Q-Jet fan myself so maybe I will just return to using those carbs, at least for my Skylark and Corvette. Time will tell I suppose. Any more tips, ideas or secrets on these carbs keep em comin. Steve

Ahhhhhhhhh. Information overload in process here. LOL. Thanks for that thorough replay to my query. I was interested because I recently put an Edelbrock 600cfm on my mildly build 302 and have been having a bitch of a time tuning it. As someone said it idles great but chugs with acceleration. I suppose it could be the fuel pump or something but it ran decent until I started messing with the settings on the Edelbrock. Was hoping that the Holleys were easier to tune but apparently they all have their good points and bad points. The Barry Grants are new but have heard some good things about them and seen them in use on some of the "tuner" shows on Discovery and TLC. I used to be a Q-Jet fan myself so maybe I will just return to using those carbs, at least for my Skylark and Corvette. Time will tell I suppose. Any more tips, ideas or secrets on these carbs keep em comin. Steve
Make no mistake, those 'tuner' shows get paid for the products they use and display. They use Grants not necessarily because they are better but because they are where the money is.
There are several good Holley tuning books out there on the market. Chances are books are out there for Edelbrock, too. I am sure you can set up your carb to run right, if you had the right guide.
Knowledge and a throrough understanding of the carb functioning and systems is the key to setting up any carb properly.

Make no mistake, those 'tuner' shows get paid for the products they use and display. They use Grants not necessarily because they are better but because they are where the money is.
There are several good Holley tuning books out there on the market. Chances are books are out there for Edelbrock, too. I am sure you can set up your carb to run right, if you had the right guide.
Knowledge and a throrough understanding of the carb functioning and systems is the key to setting up any carb properly.

I agree. The biggest probelm with carburetors these days is very few people know how to set them up correctly, it is getting to be a lost art. I am an "old" mechanic who has delt with carbs for more years than I want to remember. Each and every carb has it's advantages and disadvantages, it is really what you need from your vehicle. What I have found frustrating is there is a great deal of information on tuning Holley based carbs but really nothing on the Edelbrock series, if anyone is interested I have provided an extended tuning process in addition to the Edelbrock tuning guide on my website. When tuned properly carbs are fantastic, when not tuned right they are a frustrating pain.

Just my two cents here I have had and tuned holleys qdjets edelbrocks carters etc I have had great successes and defeats with all of them. I curently have a jet boat with a bigblock olds in it. The quadjet runs the best on it I have had the holley on it at one point just didnt work that good but I spent alot of time tuning that qdjet. On a stock or very mild engine the qdjet is a great carb. I have had Holleys on my hot rod cars in the past and have had great success with them I own none at the present time. I have had edelbrocks on stock engines before and they were a great dependable carb easy to tune no complaints ever however at the present time I have one on my big block cuda with a bracket race style cam and I cannot get the lowend hesitation out of it without going extremely rich. I have found the accelelerator pumps dont squirt in the very beginning of throttle movement. I never had a problem with it on a stock engine but now its killing me I cant fixit. The problem seems to come from the design of how the chamber fills up. The accell pump has to lift up till the fill slot is exposed to fill the chamber now on the start of travel it pushes a small amount of fuel back to the float bowl till the rubber part passes the bottom of the slot then the fuel is pushed through the accell nozzles. But the first part of throttle travel gets no fuel shot. If I lower the accell pump then it wont fill up so it seems to be impossible to resolve this concern. I spoke with Edelbrock who was very cooperative with me but there answer was to put stronger springs and bigger jets in till the bog is gone. And this is a unacceptable answer to me. The problem is not when I get on it hard it runs great there. The problem is when I try to drive slow the initial letting up of the clutch it hickups and bogs which one previous post mentioned and once in a while it even backfired through the carb, although overrichining it seems to have made backfiring non exsistent. I have recurved the distributor in a dist machine and everything all to no avail. I think it is time to try a holley and see how it goes.

I started out with a Q-jet on my 350 Nova, and for everyday reliability and a good compromise between performance and fuel economy, they are probably the way to go. I decided I wanted something new, so I ended up buying a new Holley 650 spreadbore (model 4175 I think) with vaccuum secondaries. Just bolted it on out of the box and set the air/fuel. It worked great. The electric choke was a true pleasure. Pump the accelerator once and turn the key. This carb was like having fuel injection. No more waiting for the car to warm up before you could put it in gear. Just start her and go. The only thing was it ran a little on the rich side. A few years later I switched to a 650 Speed Demon with vaccuum secondaries (my present carb). This is the carb I'm sticking with. It seems to pull harder than the the other carbs I've had. It does run a bit rich, but I just got the jet kit and should have that straightened out once I jet it down a shade. As far as I know the Demon carb is based on a Holley. Barry Grant used to modify Holleys to run on his race cars and this is how the Demon came about. It is BG's version of a Holley. I even think the first BG carbs looked identical to a Holley. As for the Edelbrock carbs, I've never owned one, but my buddy had one for a very short time. He couldn't get it to work right so he got rid of it. He now has my old Holley. So my vote goes to Demon/Holley with the Q-jet a close second. :2cents:

Just for an update I installed o2 sensors in the header collector and monitored it with a graphing oscilliscope just to confirm what I had thought. I got the accellerator pump problem worked out and also tried going to a larger nozzle pump with no success. No doubt when you get on the gas it goes lean even though the jets were way to rich for my setup. I tried everything and spoke with edelbrock who were very helpfull. but in the end I installed a carter afb carb on my car and poof problem is absolutely 100 % solved. The lean spot when you get on it is no longer showing on the o2s. Only a normal tip in little blip. In a 6sec screen capture the eddlebrock goes lean for 3 sec at its worst. Usually only a second or two. The carter was on loan so now I am not sure if I want to go with the Holley or the carter but it wont be an edelbrock. I have heard from many 750 eddy people of this problem. In the past I have only used 650 versions and never had this problem. Now I am hearing that the 650 doesnt have this problem only inherent to the 750. Also the car idles smoother with the carter carb.

hands down holley is the better card and i dont mean looks ,the rite size carb for your application,more so on track applications,ive never seen a edeljunk on any 12 second car ,maybee edelbrock will change their accelorator pump design and fuel bowl capasity,to compete with more aggressive cars,and as far as cold starts ive never had any problems,just figure out how manny times to pump your gas when you go to start your car in fridgid weather,thats my 2 cents,and as far as a grant and demon take a good look at those carbs they started of as holleys.(they do make one of the best manifolds )and a decent set of heads

I like the Carter 750cfm AFB Super Quad . This is about the same as a Edelbrock 750 . I had a lot of Holleys and changed lots of blown out power valves . Q Jets are OK but always leak down even with fuel well repairs made . :wink:

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