applejacks

Hello! Can anyone point me in a direction for researching which carbs would work best for a dual quad set up?

I have a '69 Charger with a 440 and 727 auto, 3.91 gears, E-Brock Air Gap intake with a new E-Brock 1407 (750cfm) carb. Cam is a mild E-Brock with a RPM range of 1500-6000. I'm not sure if it's been bored, but I assume it has.
I'm just going to be driving on the street with the occasional stop light burn-out. I don't know how to determine if I would be better off getting the E-Brock combo set that has the 2 600's on it (about $1200) or get another 750 and piece the set up together (about $925).
The car had a Holley 850 double pumper on it when I got it, great at low end, but a bit to much at top end. Of course the motor need dialed in, but not real street friendly. I will NOT be putting Holleys back on it. Good carbs, I just dont have the knowledge to keep them tuned and dialed in.
Any references would be most appreciated. Thanks in advance!
-Aaron

TVLynn

Personally you should keep the 850 and do some tuning. If you go the E Brock get the 600's
Many years ago I ran an 850 DP on a mild 383

Archer

aj -

The odds are you'll always do better performance-wise with a good modern single 4V set up. Unless you really need the cfm (again, highly unlikely with today's carbs), 2 x 4V is more for looks or nostalgia. Don't laugh, I was thinking about that myself ...

BTW - for better streetability, a 750 DP would probably serve you better. (I'm running an 850 DP on a similar engine, because I used to do a lot of racing, it is over kill for the street. I'll drop down to a 750 one of these days...)

Archer

440roadrunner

With that cam, 2 fours is a waste of money. If you don't have headers, get a set, will give you more power than 2 x4's

You ESPECIALLY do not want a pair of 750s on there

I think the old original 375 hp 440's came with about a 750 AVS

applejacks

Thanks for the replies!
I am running headers, and have Mallory electronic ignition (coil, dist, etc) to go on it yet.
I've heard that a good 4bbl will hang, if not out do, a 2 4x set up, but ever since I was a kid I've always wanted dual quads, mainly for the looks and wow factor when I raise the hood. I just think they look really sexy.
I dont show or race the car (well, down the block with some of the local street rods now and again, nothing serious), so I'm not out for the 'Hey, look at me, I'm Billy Go Fast'. I'd just like my car to be set up they way I've always visioned it...but correctly, or close to it
Thanks again for everyone's time!
-Aaron

BuckNeccid

Aaron, figure what CFM your engine needs, divide it by two, and then get two carbs of that size. The only benefit I can see is that with really small carbs, you get a faster air velocity and less loss of torque.

I have a friend who loves the 2x4 set ups, and has put 2 edelbrocks on top of one of their flat intakes on the last few cars he's built, with GREAT results. His latest is a 440 in an R/T Cruiser, yea, a performance PT Cruiser.

scotts74birds

I guess if you used a pair of 350-400 cfm carbs, it wont be too bad. The Eddy intake will make it ALOT more driveable, and responsive than a tunnel-ram intake. So I guess thats a plus. IMHO, a 3x2 set-up is a much better choice, and is a Mopar classic.

applejacks

Hey Scotts, I've always been told that a 3x2 set will outperform dual quads, but they are tough to dial in, get synchronized with one another, and that they require more maintenance...Just word on the street around these parts. No one in my area runs them, and I seriously doubt anyone in this pos of a town and state I live in knows anything about them. I'm very reluctant to consider that option, but it would look tremendously cool!

scotts74birds

You need to hang out with a smarter crowd. This place is a good start! On a Mopar 6 pac, the engine primarily runs off the center carb [appx 350 cfm]. The two outer carbs can vary in size, and act like 4 vacuum secondaries! Tuning is not as hard as you think. Info is all over the web. This can make for good cruising. And changing the springs in the secondary carbs will affect when they come in. Heres a small bit of info on it http://www.youtube.com/watch?v=S6LPMqvL-G4

applejacks

I definitely agree with you on hanging with a smarter crowd! Awesome video! Thanks for sharing and I'm gonna check in to this asap!

Archer

Aj -

Gonna have to disagree with our TV expert here. You're going to need a lot of displacement and a lot of RPM to ever need or use 1350 cfm. If you look at the Holley charts a moderate 440 reaching 6K will require about 800.

On a mild to moderate street engine, both 3x2v and 2v4x are more for looks. The advantage the former is the small primaries and to the latter more reliable (easier) linkages.

If that's what you want, then go for it! Just know what you're getting into. At lest one local guy with a fairly hot 440 swapped out his 3x2v for a single big (think 1,000 cfm +/-) 4v and couldn't believe the improvement.

The cool thing about street cars is that you cn do what YOU really want.

Archer.

BuckNeccid

I've been hearing people say "ya gotta syncronize a 3 deuces setup" for almost 50 years now, and even said it myself before I got the first one. The only reason I can figure for this is that they think all three work at the same time, like a motorcycle.

Archer is right, on the street with most engines, you'll never need all the flow that a six pack will give, but they DO work good, and the looks will give you lots and lots of WOW factor. If it comes to all out power, delivered reliably, it's almost always a single 4, but multi carb set ups are great for dropping jaws, and if they are set up correctly with vacuum secondarys, you'll never have then opening more flow than you need, but with the six throats, you still get good low end power.

On a 307, 4 spd, 3.08 geared 71 Camaro (Iknow, I know, GM< YUCK...) I pulled a trailer to NM from OH, and got better than 20 mpg doing so, yet, on the open highway coming back across TX on I-10, I had a turbo Trans Am try to pass me, and for over 400 miles, he wasn't able to. At a fuel stop, he pulled in beside me and DEMANDED to see what I had under the hood.

Done right, not listening to the street guys who've never set one up, a multi carb setup can be very streetable and fun

Silverick

Great video share! Very informative. Thanks!

applejacks

Hey Archer, Thanks for the input. The 750 E-Brock I have gives plenty of juice for my set up. I have no intentions of building it bigger etc. When seeing the cost of a 3x2 (I talked with Summit today), the 4x2 is more than likely what I'll be going with.
And your right, I'm doing it for the looks. If I gain some performance that will be icing on the cake. The cost of looking cool aint cheap lol!
Now to decide, 1 air cleaner or 2

I appreciate how helpful and informative everyone has been.
-Aaron

bboogieart

I say be true to your first intention. Not many use Duals anymore. Real attention getter when you open the hood. Once you get the set-up dialed in, post up pics and how to. So I can do a dual quad on mine.
Oh definately two small air cleaners. Wanna see those carbs.