No matter what forum you go to, when it comes to recommending a carb there will be people automatically saying Holley will offer more performance. I don't think I've really read a comparison between the two where both had equal time. I don't want to see so much which one is better but I think it would be interesting to see how both compare with some in depth tuning on the same engine and same size CFM carb. Just how much is a Edelbrock capable of both in power and responsiveness? We all know what a Holley can do.  

I ran a holley for a bit, then it leaked. So i bout a eldelbrock performer. I am very pleased with it. I get good throttle repsonse, what I think is good power, and good fuel milage. I manage 13 mpg out of my 454, given I have a 3.08 gear ratio, but I dont exactly drive it easy.  

I have one on my 66 Mustang and had one on my F250 that had a 460. Great street carb but it would be nice to see how they compare in power on a level playing field.  

On my Grand Prix with a Chevy 350 I've ran a Holley 700 dual feed, and an Edelbrock 650.

Both carbs were "out of the box" The only change was rejetting the Holley. The Edelbrock was a lot more responsive and seemed to give me better power under 2500rpm. The Holley was weaker down low but really picked up with the RPMs. I actually liked the Edelbrock better since it was a daily driver and performed better where I actually needed it but I switched back to the Holley because the fuel milage was 20mpg to the edelbrocks 16mpg. Although I probably could have tuned the Edelbrock to get it better.

Holley's shine when it comes to being able to easily adjust almost all aspects of tuning.  Edelbrock, and AFB's in general, do not have the aftermarket support and the ability to change the fiddly bits, like air bleeds and such.  Sure you can do it, but you'd have to drill things out and generally make what you need once you get much beyond jets, springs, rods and squirters. 

One other aspect of the Holley design that I think is superior is how the accelerator pump is fed.  From teh bottom of the bowl.  The AFB design feeds from about the middle of the bowl.  SO if you car has been sitting a while and some of the gas has evaporated you have to crank and crank to fill the bowl, then it'll start.  The fix is an electric pump, though it's be nice if Edelbrtock redesigned that feed.

Steve

I like the edelbrock for the street has great manners and seems more reliable than most holleys. Not to mention it keeps on going even soaked in mud  

I have a buddy with a dyno and we have played the edelbrock / holley game. Even though he is a big edelbrock fan the holley wins out on some engines and edelbrock on others. He does have a modded edelbrock that tends to win more often over the stock holleys but they make about the same power. It is all in the engine combo and carb setup.  

Their is a good portion of power tuning in a book called "How to build big-inch chevy small blocks" by Graham Hansen.  It goes into detail about carb selection and how different Manufacturers rate the CFM (cubic feet per minute) differently also.  Edelbrock rates its carbs in a dry flow which makes them seem to flow more because their is no fuel to displace the air entering into the carburator.  Holley and Demon both rate their carbs at 1.5"HG in wet flow.  Also something else that you have to consider, is the carburator a duel feed or a single feed inlet.  I have read and talked to many "old" carb pros that reccomend any single feed carburator, such as an Edelbrock, carter, and quadra-junk be used on engines that do not make more than 400 horses.  Fuel starvation is kinda important to avoid at WOT!!!
If you look at the book mentioned at the top (I am sure that their are others too) it starts on page 101 and goes into a ton of detail about which carburators are better suited than others.  

I understand this is why the old timers used 6 to 8 Strombergs. Not for CFM but to have sufficient needle/seat flow. Now I think we're getting to some valid points, thanks.  

It is very easy to add a second fuel feed to an Edelbrock carb.  The other side is merely plugged and it's simple to drill and tap for another fitting.  I believe the AVS version already comes that way and Edelbrock has a premade line to feed it that should work on the Performers too.

As for Edelbrock rating thier carb dry vs Holley/Demon rating thiers wet.  That makes sense seeing how a 750 Edelbrock seems to be a better street carb than a 750 Holley, out of the box.

Steve

had a holley hated it,can't let the car sit for too long with out all sorts of mayhem.tried the edelbrocks,love them.i silly love them i eat them for breakfast mmmmm 750 performer and milk!!!!! my camaro has the 750 cfm i removed the entire choke assembley.what a beast,troddle response like it was fuel injected.car sits all winter,'cept for a lot of cranking to fill her back up she never lets me down,easy to tune.cheaper to own then the unholy holley.no gas stains on my mill.yummy i think i'll have a second bowl of performer pops,snap crackle zoom zoom.my 55 chevy with a very nice 427 bb has the performer rpm q-jet.tastey.run around town on the primarys she behaves,grams could drive it.stomp that pedal like there was a la cookarocha under it stealing my socks and mr seat back meets mr butt crack and good mileage to boot.down with holley up with vic and the crew.my next big block project for dad's 39 chevy rod will be a 496 stroker,can't wait to try the new 800 cfm avs,maybe by the time i get it don mr 'brock will have 850's or 900 cfm's.i can just taste it now,plus a snazzy toy in every box.it's all part of a delicous performance breakfast!  

No doubt the edelbrock is by far the best Carb for ease of tuning and maintenance, however a properly set up holley should out perform the edelbrock hands down all across the power band. The main problem is that most of us gearheads just  don't understand how to properly tune and maintain a holley and want a carb that gets the job done faithfully.

And I know someone will respond by saying Carbs are dinosaurs go Fuel Injection, my arguement for that is... If it's carbed, and not running I check for fuel and fire and can fix it, if it's fuel injection I am lost, and can't afford to fix it anyway. lol Keep em burning guys

a bit contradicting no? you say we gear heads just don't understand the holley tuning procedure and we might be missing out on something better than the edelbrock but your unwilling to learn and take advantage of the fuel injection.look at your everday car.our newer fi'd cars go 100k plus now and pretty much never fall out of tune,the ocasional o2 censor maybe unless it's crappy ass gm tbi and that stupid iac motor,they always go on me!.you can let a fi'd car sit for long intervals and they run fine after.but 1 little snot ball in a carbs bowl or plugging a jet and viola!! gas stained engine bays,late night thrashes torn gaskets,cats and dogs living together!!!! carbs are evil,people who can tune carbs are even eviler,and the eviliest eviler is people that claim to be able to tune carbs then leave a hole in the ozone from the muck that pours out of thier tail pipe as they exit cruise night! i love a mouthful of chewey emissions i don't know about you!!!!  

It's only 10:30am and it sounds like you've hit he bottle pretty hard. As for the Carb vs. FI it takes a much smaller snot ball to plug an injector not to mention carb's don't make holes in the O-zone, infact they Create O-zone, unfortunately it isn't high up in the atmosphere where we need it.  And it is the Catalytic Converters,EGR, AIR pumps that eliminate most the emissions. 

To keep to the topic at hand, I prefer the ol' Q-jet, my friend tried the Edlebrock, Holley and the Q-jet on his 383 Camaro and this is what I got from him:

Holley - Most power, worse mileage, and the metering blocks plug up to easily (or something to that effect)

Edlebrock - Same power as the Q-jet, middle mileage, and no reliability issues at all, consequently this is what he ran with in the end.

Q-jet - Same Power as the Edlebrock, best mileage, kept developing vacuum leaks some where on it.

I don't think he ever had to mess with the Edlebrock, but I know he rebuilt and went through both the Holley and the Q-jet a few times each because he really wanted either more power or better mileage but the reliability was too much of a sacrifice. I've got three Q-jet powered cars and never had an issue with them.

three quadra-jet powered cars? you have to keep switching that 1 carb around or each car has it's own? maybe it's a dumb ? i dunno call me squeaky like a new sneaker on a fresh gym floor.also injectors don't clog,that's a myth.the amount of fuel pressure  used on an injected car would require you to drop your gas tank,slice it open then use it as a mold to build sand castles at the beach or perhaps,start off with diesel fuel at the pump then switch to gas when the realization kicks in that you didn't need that last devil dog to impair your thought process.