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Technical Can 6 2bbl carbs perform as well as 2 4bbls?

Discussion in 'The Hokey Ass Message Board' started by 53 hemi, Aug 15, 2022.

  1. 53 hemi
    Joined: Jan 8, 2009
    Posts: 501

    53 hemi

    Just curious - I'm running 2 Edelbrock 500 coming carbs on a 354 Hemi and the performance is fantastic, but nothing looks as cool as 6 Strombergs.
  2. Hollywood-East
    Joined: Mar 13, 2008
    Posts: 2,007


    Agree 100%
    Had to sell for a real state transaction, Never fired nos set-up, went to NYC.. 1661571-1eda1a88862d9060ae4cc5bc9c68b7dd.jpg
    chevy57dude likes this.
  3. Short answer is no. Long answer is that you can probably tune the 6x2s to be close but its a much bigger chore getting all 6 carbs happy where with dual quads you only have to deal with the 2. I have both setups on different small blocks and the dual quad motor will run circles around my 6x2s, but totally agree 6x2s just have that wow factor.

    Tim, NoelC, Montana1 and 2 others like this.
  4. hemihotrod66
    Joined: May 5, 2019
    Posts: 968


    Now a days one good 4 Barrel on the right manifold will out perform most multicarb setups...
  5. jaracer
    Joined: Oct 4, 2008
    Posts: 2,543


    Hilborn injection beats them all.
  6. 73RR
    Joined: Jan 29, 2007
    Posts: 7,258


    Hilborn is not very street friendly, strip is a different animal.
    I'm in the 1x4 group. 2 carbs are twice as much work to make happy and 6 carbs are 6 times more work.
    Some of the 60's 70's NASCAR Holleys have a certain wow factor......
  7. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 6,268


    I'd be willing to bet the dual quads will run better than the 6x2s. Likely both in terms of manners and in power numbers. Yes, the 6x2s look super cool, but dual quads look cool, too. I think you still get points for multi-carbs.
    Flathead Dave likes this.
  8. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,566


    *Except that it would be an epic failure on the street.
    Truckdoctor Andy and seb fontana like this.
  9. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,566


    That's a proven fact.

    Why? Venturi velocity. Combined cross-section versus air velocity.

    So many people are going for the "cool look", and that's fine, but then thy wonder why throttle response, overall performance, and milage are all mediocre to terrible.
  10. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,566


    I had a customer come in with a 6 x 2 setup on a 283, rams horns, and I believe otherwise stock.

    It ran like chunky dog squeeze.

    When it left my shop, it ran smoothly, and accelerated without any hesitation, with good all around performance.

    The changes:

    Hidden O2 sensor bung, plugged after tuning.
    4 block off plates.
    4 grub screws.

    It left looking the same, but running a very expensive 2 x 2 setup.
  11. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,566


    Right now you have the maximum potential flow of 1000cfm (measured on the scale used for 4-barrel carburetors).

    Now, that is not delivered as you might expect.

    The primaries on an Edelbrock 500 are not 1/2 of the flow rate. The venturis and throttle blades are not of equal size. The primaries are smaller. On a 500 they represent ~36.67% of the flow.

    That's what you are directly controlling with the throttle pedal, just 366.7cfm.

    The balance of what may or may not be delivered to the engine is based on engine demand.

    If you switch to a straight or even a progressive linkage 6 x 2 setup, you will lose the on-demand function, and just open throttle blades, irrespective of the engine need for that fuel delivery potential.
    winduptoy and Truckdoctor Andy like this.
  12. I pit for a friend that makes a little over 1000 HP N/A on one Dominator 4 bbl.
    Nothing like the "WOW!" factor though... :rolleyes:
  13. oldiron 440
    Joined: Dec 12, 2018
    Posts: 3,426

    oldiron 440

    You just can’t beat a properly sized and tuned 4V carb on drivability and it doesn’t need to be a 4V. Looks is a hole nother animal. For me performance and drivability are number one but the that has a look of it’s own also.
  14. das858
    Joined: Jul 28, 2010
    Posts: 1,037


    In my mind two 4 barrels look better and perform better than six 2 barrels .
    Last edited: Aug 16, 2022
  15. That depends on the street. On my street it's been fun...
    winduptoy, Montana1 and 427 sleeper like this.
  16. gimpyshotrods
    Joined: May 20, 2009
    Posts: 23,566


    Well, you do live in the State of Confusion!
  17. jaracer
    Joined: Oct 4, 2008
    Posts: 2,543


    A few years ago, before they were sold, Hilborn was promoting them for street use. They had a video of I think a tri-five Chevy with a Hilborn setup being street driven. My race car was very drivable at low speeds even running alcohol. Kinsler was offering a conversion to use electronic injectors on a Hilborn manifold. I'm not sure if Hilborn offers the same.

    At any rate, still cooler than 6 carbs. Like a 6 carb setup is real streetable.
    Montana1 and das858 like this.
  18. lodaddyo
    Joined: May 5, 2002
    Posts: 1,250


    If you want to sell those two 500 edelbrocks. I need some carbs for my 32. Im in baton rouge.
    winduptoy likes this.
  19. tomcat11
    Joined: Mar 31, 2010
    Posts: 936


    Stick with the 2 X 4 performance. Manifold runners and therefore fuel distribution on most multi carburetor set ups (non dual quad) is usually not too good and like has been mentioned the tuning can be difficult. Dual quads are just as cool and easier to run and maintain.
  20. jetnow1
    Joined: Jan 30, 2008
    Posts: 2,166

    from CT
    1. A-D Truckers

    If your goal is to impress the car show folks multiple carbs, if you just want to drive it a single 4 barrel, racing would depend on your class. Funny how often postings here talk about trophy whores, yet the cars that draw the most attention often have multiple carbs where one would give better performance.
  21. jnaki
    Joined: Jan 1, 2015
    Posts: 9,666



    When we first started, we wanted a 283 SBC motor with dual quads. That was our response to our friend’s 34 Ford 5 window coupe that had a big Oldsmobile motor with a wide array of carburetor set ups over the different build days and weekends at the drags. That Oldsmobile powered 1934 coupe did its best in the A/Gas and B/Gas classes with just the different set ups, starting with a four barrel, then multiple 2 barrels, a dual quad set up and finally a 6 Stromberg carb set up.

    The first photo, an internet photo capture… the others at Lion’s Dragstrip in 1959.

    The fastest time was with the 6 Stromberg carb set up and the same motor components. So, it was also a daily driver and ran well doing daily stuff, high school parking spots, after school job. When he made many visits to our house, I could hear the motor and coupe coming down the street with a loud rumble. When it was on our driveway, he always stopped the motor with one last “rump” of the motor. That was worth the visit.


    When we started our 1940 Willys Coupe build, we had a choice of SBC motor set ups. We wanted a dual quad system that would do well at the drags and on the daily street purposes. So, we visited a small local speed shop. The owner had a dual quad set up sitting on the counter and a short block SBC motor on a stand next to the counter. We instantly liked where this was going.

    The owner wanted to know what we were planning on doing with the SBC motor. When explaining our build, he mentioned that the dual quad was great for the street and drags, but that the 6 Stromberg carb set up would show more power at the drags. At the time, a lot of drag racers/race cars that we had seen, had 6 Strombergs on their motors at Lion’s Dragstrip in most of the different classes, from FED racers to Altered Coupes/Roadsters to Gas Coupes/Sedans.

    He just happened to have a 6 Stromberg carb set up just for the display 283 short block or the long block Chevy motor in the storage area. So, after he made us a package deal, we walked off with a new 283 SBC motor, Isky Cam, Jahns Pistons, Chevy truck heads, and the 6 Stromberg carb package. On the way home, my brother had a smile all the way across his face.

    The motor ran fine when we got everything together. It was difficult to coordinate all 6 carbs. But, once done, it was music to our ears. Power on request… On our test weekend drives to our cruising grounds in Bixby Knolls, it was a very fast street hot rod. But, we had to check the gas usage in our small 2.5 gallon Moon Aluminum Tank, almost at every corner.

    We had no idea the total miles we could drive on one small tank. At the drags, it was a respectable SBC powered hot rod competing in the B/Gas Class. But, the results for the next several weekends just were not the best we could do with the carburetor powered SBC motor. It was fast for a hot rod coupe with the sbc +6 strombergs, but not as fast as the top racers in the class.

    So, we upped our rebuild with a boost to 292 c.i. SBC motor, including a new 671 supercharger and a new Isky Gilmer Belt Drive + components. It was one of the first 671 belt drives for an SBC motor in So Cal. The motor had to be totally rebuilt with pure “blower spec” components and the topper was the 6 Stromberg carb set up. The power was amazing and in our 40 Willys, the powerful motor let everyone know who was coming down the street, with emphasis.

    upload_2022-8-16_4-52-20.png similar motor set up
    On our test drives through Bixby Knolls, it was definitely an eye opener. We knew we had built something special and could not wait to run it at the nearby Lion's Dragstrip.

    We got close to the national record for C/Gas at 12:60 E.T. We were getting close to the 12:40 record.
    All good things came to an end, but, we had already seen and planned for a two port Hilborn Injection System for the 671 SBC motor.


    Attached Files:

    1952henry, bchctybob and rbrewer like this.
  22. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,239


    I had a street Hemi and milled the top off the intake made a plate for a single carb ran a Holley 3 barrel and the car ran much better. Multi carbs look cool but most engines can be over carbed with one carb. But I do dig crossrams and Man A Fre setups. If you just want the looks hide a carb in a blower case.
  23. Those of us that are old enough remember in the '50's most of the really fast normally aspirated ( not injected) dragsters and altereds ran 6 or 8 carburetors. Dual 4 barrels were available but I don't think the 4 barrel carburetors of the day were up to the task. A dual 4 barrel dragster would have been rare.
    jnaki and bchctybob like this.
  24. Littleman would be the most qualified to answer this question, if you do a search you can find his threads on dialing in his 6x2 carbs.

    FB_IMG_1660695126041.jpg FB_IMG_1660695105664.jpg
    hrm2k and 427 sleeper like this.
  25. PackardV8
    Joined: Jun 7, 2007
    Posts: 1,217


    Don Garlits told me he used 8x2 to get more needle and seat area to flow more nitro.


    jack vines
  26. carbking
    Joined: Dec 20, 2008
    Posts: 3,769


    On a V-8:

    6 x 2 is just double 3 x 2; neither will compete with 2 x 4 or even 1 x 4.

    Now 4 x 2 or 8 x 2 is a different story.

    Guys I knew that had 6 x 2 in the '50's tried to make them work; and then blocked off the center two. Ran much better.

    Today, it probably all comes down to the "eye candy" desires of the owner.

    winduptoy likes this.
  27. winduptoy
    Joined: Feb 19, 2013
    Posts: 3,474


    I bench race a lot with Joe Abbin....Mr. Flathead. Multi carb set-ups came up one session Curious about performance and statements made in old hot rod magazines, he started with 1x2 on a flathead on the dyno...then 2x2 and it made 20 more hp. 3x2 no more hp than the 2x2 all the way on up in carb count. We did agree the multi carb set up's in the back of the period magazines were sexy
  28. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,239


    Well he did prove that flathead could only use so much air.
  29. jnaki
    Joined: Jan 1, 2015
    Posts: 9,666



    Despite the world records set back East, when Garlits came out West in 1959, everyone was impressed with the setup of his FED. But, at his first race in Bakersfield, the results were not impressive. He stayed in So Cal to get some valuable information from So Cal racers and developers of cams/cranks, blowers, etc.

    By the time he traveled up North in California to continue his Westcoast tour, he was again setting records and impressing other racers with his skills and build, thanks to several So Cal representatives.

    If you get a chance, read the book:


    The "Three Weeks in March" tells the story behind the West Coast foray of Don Garlits, that wild driver from Florida. He had captured the attention of all of the fastest racers on the West Coast and this book tells the story of that scene in So Cal. Was that East Coast drag racer with top speeds and times listed in the Drag News, real? That was the questions asked from most West Coast racers.

  30. Jan 2002 Hot Rod magazine dyno test of several intakes on the same engine, here's the particulars.

    The Set-Ups:
    *Holley Pro Dominator tunnel ram w/2 750 dominators: 485HP@6200/438TQ@5200

    * "The Summit Combo" Wieand Hi tunnel ram and 2 Holley 450cfm: 491HP@6200/443TQ@5500

    *Eddie cross ram intake and 2 Holley 450cfm carbs: 480HO@6300/425TQ@5000

    *Eddie street tunnel ram w/2 650cfm race Demon carbs: 503HP@6100/452TQ@5600

    *Eddie C-26 dual quad intake w/2 eddie performer 500CFm carbs: 446HP@6200/405TQ@4800

    *Eddie C-357 B 3 duce intake w/3 Rochester 220cfm carbs: this one gave them problems and they cheange the cam to a [email protected] for better vacum signal but they couldn't run it on the dyno becasue it was running to lean and didn't want to trash the motor .they said that on a trunacted test between 3K and 5300 the set up made between 8 and 12 HP and TQ less than a 625 road Demon on a RPm air gap intake. which they felt was very impressive.

    * Offy 6 pot intake w/ 6 Stromberg 97 2 barrels: 350HP@5900/366TQ@4300
    das858 likes this.

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