Demon carbs...are they really that good?

[mr.b]

Thinking about buying a demon carb for my 440 b-body. would i really see that much of a performance gain? Did any of you see that much of a gain after you made the swap and how much was it? The car runs 12.3 now.
specs below. thanks

[rellik eeb]

Run Away
There no better and in soe cases "worse" than old Holley carbs. There qc sucks as does there Customer service. Thats why Summit Racing dropped there line.

I would be looking at a Proform based HP series carb. Screw in air bleeds, 4 corner idle. You wont be more happy. But if the budget allows, give the pro's a chance. I have heard good things from Biggs, and Pro Systems, the carb will be on the money for your application.

[dust]

I've heard bad about the JR series but good about the Might / Speed series

I'm going to buy a 750cfm carb and it seems that Holley may be the best for that cfm and my application, 408 cu.

[dave571]

The question is a little loaded.

A well matched carb to your combo, regardless of make, will work well.

If you have the right carb now, you won't see a big gain with a demon.

Personally, I run demon's on three of my own vehicles(a 625 road, a 650 speed, and a 750 mighty) and would never run another holley or edelbrock.

Most Demon horror stories about tunability are because of the wrong carb being selected. Either too big (an 850 demon on a 383) or wrong series (a speed demon on a car with 250 @ 50 duration cam specs).
Makes them difficult to tune.

Select the right one, make some tuning adjustments on set up and away you go.

Quick change features on the secondary spring, and sight glasses instead of the holes to pee the gas onto the motor.

my .02

[pishta]

Only way Id buy another one is from Don at FBO, he'll ask the good questions and will recommend a carb that will WORK. He'll jet it too, and offer phone support if worse come to it. nice guy too.

[ehostler]

I put a Speed Demon on my 440 and she runs great. I'll never go back to Holley.

Definately get the Demon from Don at FBO Systems. He will give you great pre and post sales support.

As far as Summit goes, they did not drop the Demon line. Barry Grant dropped them as a distributor.

[Cudadrag]

I found no difference in performance between Holley and Demon (Holley 850 DB vs. Speed Demon 850) The Demon's Billet design would suggest it would last longer and may very well be more consistent while aging but for the price difference I don't believe it is worth it. Demon uses Holley designs for a reason. The Holley HP series have been very successful. I am upgrading to the Holley 950 HP. What I have heard is that Demon can only match the HP performance with their Mighty Demon line. So why pay more and mess with Holley's proven track record.

IMO

[flipper35]

Don't forget wet v dry flow for the ratings. A Demon 850 (wet method) will flow more than a Holley 850 (dry method) so it is easy to over carb your car going from a Holley to a Demon.

[RAM MAN]

I'm in the same boat

I have a 440 4bbl in my 70 RR, there's a Holley on it now, but its set up for racing (read: no choke) and I'm going to swap it out for something better as well

thanks for the info

[bigiron]

I have 5 Demons 2 750 speed Demons, 1 7?? Mighty Demon (I forget the size but it's something odd) and 2 775 race Demons with the changeable Venturis...

The 2 race demons SUCK... they leak past the floats.. I have changed floats I have changed bowls I have had a Mopar machanic of some thirty some years work on them... all and all I have about $1400 a piece into them and they still leak.. that is even turning the regs down to 3#....

The speed demons are better they at least don't leak... we put 5 passes apiece between my two cars one with a Holly 750 and one with a 750 Speed demon. After each pass we switched carbs from one car to the other... and then made another pass... also between each pass we inspected the plugs and checked timing to be sure each had a fair chance to prove itself... I drove one car and my brother drove the other, always the same car...

All you Demon guys should try this yourselves... Their was virtually NO difference between the two as far as performance goes.... Now if you THINK it feels better that's all the good but as far as I see it I'll never buy another Demon... Not for the extra cost (unless your after that paticular look...That's why I bought them)

Of course I'm on their acceptable loss list now... after all the trouble with the two race demons... so it doesn't matter much... they have totally blowen me off...

I can't say anything against the Mighty Demon but it's just sits on a Ford Cleavland... and doesn't get driven much...

Maybe they were decent at one time but the quality control has left the building over there...

Oh... Jegs was the first to drop Demon and they picked them up again.. I talked to some of the guys and it had to do with warrenty issues... (Imagin that) Technicly Grant dropped Summit as a distributor but that was after almost getting sued by Summit for.... You guessed it ... Warranty issues... it would of happened a week later if Grant wouldn't have pulled out... just so he could say he dropped them.... at least that's my understanding of that situation.

I could go on and on and on and on ....... but I think you get where I stand with them....

[dave571]

Originally Posted by ehostler

As far as Summit goes, they did not drop the Demon line. Barry Grant dropped them as a distributor.

Absolutely true.

Barry Grant dropped summit, not the other way around.

If anything, no one can say that Barry Grant doesn't have balls.

[dust]

Originally Posted by bigiron

I could go on and on and on and on ....... but I think you get where I stand with them....

Go ahead, I'm learning ^_^.
This thread has some great info, I am considering which carb to get and you guys are helping me in my decision by posting your experiences. Thanks.

[eric414]

I second the race demon are junk.when they first came out i had to have one.after a year of messing with it trying to get it right it the carb had a new owner.EBAY

[DartGT66]

I heard that Summit dropped the line because of too many returns. Wether it was BG who dropped Summit or vice versa doesn't matter much, the reason was that + Summit didn't egt the crabs cheaper than other dealers despite of the volumes they sell. Demons have theoretically nice features, but if they are sqrewed up with bad quality control, it doesn't matter a lot. If you look at the features, they are actually very cheap carburators, but the cheap price doesn't seem to come out of the air. The most common problems I have heard of are loose throttle shafts and metal shavings here and there, unpossible to remove them from the metering blocks. I have had only one race demon, and it worked OK, but pretty many friends of mine haven't been as lucky. A Holley for me, please.

[Fast_Eddie]

What I heard is that the reason for the number of returns was solely because the techs at Summit were continually selling people the wrong carbs for their application.

I don't have any experience with their race carbs, but I have had nothing but great experience with their street carbs on 3 different cars.

I too, won't go back to a Holley.

[rellik eeb]

The whole reason for there design is for better tunablity......thats waht I dont get, you gotta buy a certain carb with a certain camshaft. I picked up a 850 speed demon long time ago. With a huge camshaft it wouldnt idle, made a call to BG they said the wrong carb, nothing I could do about that, not there fualt, but if there carbs were so adjustable, why couldnt one make it work, they have NO screw in bleeds, The guy I got it off of said it just flooded his engine (new Carb) after I cleaned the metal machine chips from the bowls, and center section, it worked ok on a mild 440. But the Old 850DP went back on the hot engine and never gave me trouble.

They should change there name to BJ
BIG JUNK.

I run nothing but HP Dominators now, and are the ultimate in power goes.

[mr.b]

thanks for the info. i did talk to don at fbo and he recomended the 750 mighty demon. i wonder if the double pumper will give me a better launch or 60' time over my 6-barrel? It seems that some of you are happy with Biggs. What about AED carbs? What are cost compared to the Mighty Demon?

[3276/A-Body/71]

Why does his PS car not make the NHRA fields? Just wondering.

[ehostler]

Who are you refering to? Also, what do you mean by PS?

[pishta]

Power Steering?

[littlecampbell]

Originally Posted by flipper35

Don't forget wet v dry flow for the ratings. A Demon 850 (wet method) will flow more than a Holley 850 (dry method) so it is easy to over carb your car going from a Holley to a Demon.

Both wet flowed by the way. Hey Dave nice pics from Mission. You have lost a few lbs.

[dart joe]

Originally Posted by mr.b

thanks for the info. i did talk to don at fbo and he recomended the 750 mighty demon. i wonder if the double pumper will give me a better launch or 60' time over my 6-barrel? It seems that some of you are happy with Biggs. What about AED carbs? What are cost compared to the Mighty Demon?

Mr. B, call jesse at Bigs, he will hook you up with the RIGHT carb for your needs, and it will be dialed in for your combo, as far as the 6-barrel, if you have them working good there hard to beat.

[dave571]

Originally Posted by littlecampbell

Both wet flowed by the way. Hey Dave nice pics from Mission. You have lost a few lbs.

Hey LC. Yes I've lost 35 pounds. Where were you this year?

AS for the carbs, the holleys are wet flow tested, not wet flow rated.

The statements about the demon 750 flowing more than a holley 750 are accurate.

That's where people get into touble. Figure they could use a little more carb than the 750 they have on thier 440. See the demon's features, and get an 850 demon. All of a sudden too much carb, and a story about how hard to tune they are.

Everybody has thier own opinion of course.