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carbs, who likes what?
I am building a 408 stroker, afr 185 heads, edelbrock air gap, comp roller cam, (haven't completely decided on size), I am stuck on a carb. Holley, Edelbrock ,Speed Demon, I have heard the least amount of bad things about the Speed Demons, maybe because they are the least used? Any body got experiences to share, I'm sure this may open a BIG can o' worms!:LOL:
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Go with a Holley or better yet an EFI unit.
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The first thing to do is to size the carb correctly! 650cfm..750cfm..850cfm...etc! From there the possibilities begin. Open up a summit catalog these days & you find that that carb market is crowded. Personally of the 3 you listed my performance preference would be #1 Demon(basically an updated holley) #2 Holley(Classic looks & performance) #3 Edelbrock("Can" take a lot of work to set up properly but can be a great running block)
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Barry grant
I like the holley hp series or the speed demon. I have a 650 speed demon and its a great carb BUT when I got the carb it would not run right and I had to take it apart and found some junk between the metering plate gasket and the center section.
After a good cleaning its been a great carb. Other than cleaning and rejetting I haven't change any thiing on the carb. On the dyno it gives a very consistient air fuel ratio. I personally have not had a holley hp but my buddy has one on his car and it was a good carb. Just had to be rejetted I would not go fuel inj. The technology in these new carbs is amazing. Later Good luck kelley |
Have heard a lot of very good reports from people who ordered their Speed Demon carbs from Don Gould
www.4secondsflat.com Don has been building carbs for all sorts of high performance street and race cars (track and drag) all of his life and knows motors and what makes them go. When you order a carb from him he wants your car specs (weight, motor, cam, cam duration at .50, etc.). He offers and recommends his "optional service" of tearing down the new carb and putting it back together again, along with setting it up for optimal performance on your motor. He will also speak with you over the phone during installation (or your mechanic) to give recommended distributor and timing set points for the motor. He has never had a Demon carb that HE has set up, go back to the factory for warranty work. I am ordering one from him for my 302, once I determine which cam I'm going to mate with the Trick Flow heads I'm ordering. Good luck! Rick |
I second the Don Gould reference.....
Had a finicky Holley 4150-9379, so replaced the main body with a ProForm, new throttle plate, etc. Still just didn't seem "right." I started looking at Mighty Demons and read some of Don's articles on tuning and such. Gave him a call and he talked me through the pros / cons of various units. He also talked me through setting the right timing advance mix between intial and mechanical, and also sold me some custom advance bushings for my MSD distributor.
Bought a Mighty Demon 750cfm from him. He checked it out, tuned it, and sent it to me. I bolted it on, started the car, and never touched an adjustment other than minor float level adjustment. Car went from struggling to idle at 900 rpm, to now idling at 600 and basically starts right up every time. That's the kind of service I like. They respond to your calls and emails, will talk through stuff with you, provide technical info, support you after the sale, and the product performs as promised. |
Holley with vacuum secondaries and no rear jets to change out. Simple and effective. Only two items if you need to tune it to your engine (and you will need to):
Power Valve and Jet Size. Once those are dialed in, your done! |
EFI
There's a reason no new cars come with carbs any more - EFI is better. Yes, it's more expensive, but it is infinaitely tunable - with a computer, and there's no guess work - always the right mixture, all the time.
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I've had an 850 Holley on my 418 stroker since the car was new. The carb was massaged by Jet Performance, Stage 3. Barry Grant carbs are good ones too, but I liked the "original" look of the Holley, and some of the Barry Grant models look like a giant potatoe on the intake manifold....sorry guys.
No matter what carb you get, take the car to a chassis dyno and an air/fuel meter and dial in your motor's A/F ratio for maximum power and driveabliity. I've seen so many guys driving around with over rich carbs that no only waste gas and emissions, but leave horsepower on the table by not dialing them in correctly. Next stop for me is stacked EFI like the previous thread touted. |
I run a 850cfm Holley on my 427 and have absolutely no problems with it. But I've used a Speed Demon on my other car and had no problem with that as well.
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When it comes to carbs, bigger is not always better. This is what I suggest 650 Holley double pumper, 1:1 Moroso secondary linkage kit. 2-4 hours on a chassis dyno tuning and tweaking.
Your done, go drive the car. Bill S. |
Here's a thread regarding the Barry Grant Speed Demon series, Some light reading, be aware of CFM's, Holley uses air to advertise their CFM's and BG uses liquid or vice versa I can't remember. Regardless it's not the same, my BG was too large where as the 850CFM from Holley which Ford Motorsport would have worked just fine. http://www.clubcobra.com/forums/show...threadid=62391
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as a rule of thumb, you can take the cubic inches of your engine and multiply it by the max RPM and divide it by 3456
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The Holley are rated with air only, the BG are rated with air and fuel (wet flowed) and a 650 BG flows 720cfm if you rate it the same as the Holley.
Talk to someone who does this a lot (Don) and they will get you the right size, no guess work involved. |
I don't have the same engine size or combo as you do.The car came with a 351 with Edelbrock Victor Jr heads, unknown specs but lopey cam, a Edelbrock Victor Jr. manifold, and a Holley 750 double pumper. It hated running under 2500 rpm and since I have 3.10 gears and a Tremec 3550 with the tall (.67) overdrive the combo didn't work well for me. I now have a Holley Street Avenger, 670 cfm with an Edelbrock RPM air gap. I lost about 30 hp at the top but get 322 at the rear wheels. The car is very driveable. The "Dyno Shop" told me to be prepared to spend a lot more dyno hours setting up a Demon, they steered me to the Street Avenger and I love it. You would probably need a 770.
Good luck - John |
Cleggy,
I have a 950 cfm Davinci on my Keith Craft 427 / 482so. Have had no problems and the car idles great, around 900 rpm's. Allen |
Boy, oh boy. The worms should be all over the floor by now.
It seems that if you ask enough folks, even professionals, you'll find out that every carburetor out there is a total piece of garbage when compared to their personal favorite. I have an Edelbrock on one car, a Holley vacuum on one, a Holley double-pumper on another, and a Mighty Demon on the Cobra. ALL of them work great. They're just all a bit different to set up. Personally, I know how to tweak the Holley-types better than the Quadrajet types, but I think that the latter is more flexible when it comes to fine-tuning, as you don't have to break out the drill bits and risk overdoing it. Needles are easier to play with than drill bits. If I were starting at the zero-knowledge point, I'd buy a Rochester tuning book and a Holley tuning book to see which you are more comfortable fiddling with. Although I own more Holley-types, I personally think the Quadrajet-type is easier to mess with without messing up. I just became familiar with the Holleys early in life. I guarantee that others will completely disagree. |
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Quote:
I just wish I would have done this sooner! YMMV, Randy R... |
Bought a 650 Speed Demon a month ago to replace the (too big) 750 Holley that is currently on my car. I thought the Speed Demon could just be bolted on and go.....but oh no. Upon initial start-up it sprays fuel out the sides of the carb (where the throttle linkage goes in).
Barry Grant's tech line says I need to take the float bowls off and adjust the floats (even though they were supposed to be factory adjusted). I haven't had time to mess with it, so I have a $400 workbench decoration now... Holley is back on and running fine. |
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