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Hot Rods Are you running multiple carburetors?

Discussion in 'The Hokey Ass Message Board' started by HOTRODPRIMER, May 23, 2021.

  1. Lets talk about how well they work, are they reliable?

    What engine are they on? Are they new or rebuilt? HRP
    3W JOHN, Deuces and dana barlow like this.
  2. Funny...I was just talking to my kid about this last night. We were talking about running two fours and his only recollection of me running multiple carburetors (three Holley 94’s) was that multiple carburetors was a pain. So, my only experience with multiples (that I actually drove) was two brand new Holley 450’s years ago that worked great on a pretty healthy 350 Chevy and my bad experience trying to rebuild three worn out 94’s on a 292 Ford. So, seems results may vary.
  3. jimmy six
    Joined: Mar 21, 2006
    Posts: 15,073

    jimmy six

    Multiple carbs have been covered here on the HAMB many times and extensively.
    Dual quads on a yblock, 5 years now, not coming off. 1953 carbs on a 1957 manifold. Progressive linkage. In my opinion you need a Unisyn to set any system or similar unit. You need to purge, kick them in the butt, monthly with todays fuel. Many here can help, especially carbking. 03A32A2D-9B4A-40B6-B4C2-E4ACDBC1913B.jpeg 3-2’s on a 311” GMC, 1960 Holleys 280 cfm on a 1950 Howard intake with adapters. Progressive linkage, tougher to run due to intake design, many places to have vacuum leaks. Good luck. 85A319EF-DD4C-4A5D-8EA3-F3B8C3CCA058.jpeg
    Last edited: May 23, 2021
    rpm56, Duellym, Elcohaulic and 11 others like this.
  4. egads
    Joined: Aug 23, 2011
    Posts: 1,419


    2 350 holley's 2 barrel's on my 312. Straight linkage, t-5, 370 gear. Get's about 18-19 mpg running 75 mph. Never given me a problem and great throttle response. Tripower on my 63 Cat in my avatar, also run's great.[​IMG][​IMG]
    rpm56, okiedokie, mctim64 and 11 others like this.

  5. Granted, and this is not directed to you but there is probably nothing that hasn't been posted multiple times and there are many that haven't read the threads or newcomers that are oblivious to past threads.

    There are a few members that delight in pointing out -" This has been posted many times" but just relying on the older threads and never posting updates what good would the HAMB be? HRP
    wackdaddy, Hemi Joel, TagMan and 23 others like this.
  6. I have run 3 two bbl carbs on a few engines (SBCs, FEs and Flatheads) with zero issues.........both straight and progressive linkage used. Carbs ranged from 94s to Rochester 2Gs. I have also run two 4-bbls (Rochester 4GCs) on Y-blocks without any issues.
  7. squirrel
    Joined: Sep 23, 2004
    Posts: 56,274


    I've had a pair of carbs on a blower for over 30 years now...they're just as reliable as a single carb, although when it's rebuild time, you get to do more than one.

    It's hard to find a 1500 cfm carb, to feed a blown big block, so two carbs, it is.
  8. 4ty
    Joined: Jan 1, 2009
    Posts: 272


    I've got two chrome 97's on an Almquist intake, Kogel Hi-Comp heads on my 40, Ronnie Roadster did the tuning. Runs great ! !
    Paul in CT
  9. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 1,684


    Danny, I suspect that you knew it was a Pandora's box you opened! And I suspect that the responses will be either their great, or they not. I myself am a fan of a bunch of two barrels on top of an engine - 4, 6, or 8. Having said that, to be successful at it you need to plan ahead from the start of the engine build:
    1. Carbs need a certain amount of air flow to meter correctly. The more carbs, the harder that might become. So don't go crazy on head intake runner size and select a cam that has decent idle vacuum.
    2. Depending on the intake configuration, you may need carb spacers to help carb metering.
    3. Know from the start it's not a bolt it on and drive it kind of deal.
    4. Also know that yes, you will leave a bit of HP on the table to get that look. I am OK with that as 99.5% of the time you don't use what you have.
    5. You need to really understand how a carb works. And know that until you get it sorted out, you will be working on them.
    I could ramble on about specific configurations, but there are too many. Multiple carbs are not for everyone. But when properly executed, they are reliable, perform well, and in some cases get decent mileage.
  10. Budget36
    Joined: Nov 29, 2014
    Posts: 13,443


    I’ve never had multiple carbs before on a car, but sure love the look.
  11. dana barlow
    Joined: May 30, 2006
    Posts: 5,138

    dana barlow
    from Miami Fla.
    1. Y-blocks

    I started out with Ford Y-blocks,did lots of other engines in other rods.
    My first "Y", I still play with, it was a 4bbl. and it did run well with it,it looked n ran better with 2x4 set up{ match set of carbs off a Cady on the Thunderbird 2x4 intake< I loved it,best runner/// tell some guy offered too much $$$$ for the 2x4 set up,at a time I needed $.
    Went back to 4bbl for a little,but wanted multiple carb look,so made my own 4x2 intake out of cutting up a old drive shaft ,plus linkage an fuel rail self fab. It's fun,but takes more tinkering then any other combo. Eye candy of it is why,I keep playing with 4x2 fun.
    Carbs,no matter how many{Except if too many} run as well as owner knows how to play with them.
    Bobtail 28 roadster DB's.jpg
    Last edited: Jun 2, 2021
  12. Speed Gems
    Joined: Jul 17, 2012
    Posts: 6,433

    Speed Gems

    You know, it's interesting, i collect HOT ROD magazines from the 50's and 60's and i bought some STREET RODDER magazines from the late 60's early 70's many of the hot rods have multiple carbs and most of the street rods have one single 4BBL carb.
  13. goldmountain
    Joined: Jun 12, 2016
    Posts: 4,507


    Multiple carbs look pretty. Look how many are on the Munster coach.
    3W JOHN, Just Gary and HOTRODPRIMER like this.
  14. Bigmac48
    Joined: Apr 3, 2017
    Posts: 625

    from Dundalk Md

    20210523_173931.jpg 20210523_173925.jpg View attachment 5070865 To pretty to change ,not the fastest but the hottest looking motor I've ever owned . My 1st flathead .
    Last edited: May 23, 2021
    3W JOHN, wicarnut, jimmy six and 5 others like this.
  15. Speed Gems
    Joined: Jul 17, 2012
    Posts: 6,433

    Speed Gems

    3W JOHN and HOTRODPRIMER like this.
  16. KoolKat-57
    Joined: Feb 22, 2010
    Posts: 3,077

    from Dublin, OH

    Factory Tri-Power on my '57 Pontiac w/progressive linkage. recent 021.JPG
    Last edited: May 30, 2021
  17. KoolKat-57
    Joined: Feb 22, 2010
    Posts: 3,077

    from Dublin, OH

    Dual matched set of primary/secondary 60s AFBs on the 392 Hemi in my Roadster. IMG_0228.JPG Never had a problem progressive linkage KK
  18. carbking
    Joined: Dec 20, 2008
    Posts: 3,739


    BEFORE I was bitten by the "buy American" bug; I played with British sports cars, all of which had at least 2 carburetors. Owned and restored several; have tuned hundreds.

    The bug bit me about 1975.

    Current multiple set up is a Ford FE engine, with (2) genuine Carter 4759s AFB's (modified) running solid linkage.

    Went untouched for 19 years, but need to rebuild them now as the truck sat in the air conditioning shop having a factory AC unit installed; and it sat long enough for one of the floats to sometimes stick.

    Driveability is superb. Fuel mileage is terrific. Reliability has been terrific until they sat too long without starting.

    Learned long ago, the secret to multi-carbs (or a single carb for that matter) working well is to start with a carburetor or carburetors that have a reasonable chance of working well on the engine. Check the second line in my signature block.

    mrhp, 3W JOHN, Driver50x and 5 others like this.
  19. uncleandy 65
    Joined: Jan 14, 2013
    Posts: 4,148

    uncleandy 65

  20. bchctybob
    Joined: Sep 18, 2011
    Posts: 5,355


    I hadn't really given it much thought but I've had quite a few cars and boats with multiple carburetors, starting with the family ski boat my Dad built with a '60 Pontiac engine with the factory 3x2 set up when I was 15-16 years old. Looking back, most of my cars have had multiple carbs. Lately, my '31 Tudor had three Rochesters, so did my roadster when I got it. My Austin has two AFBs on a 6-71.
    But the new version of my roadster will be the biggest challenge yet - six 97s on a Weiand Drag Star. We'll just have to wait and see if I have the patience for that one....
  21. kabinenroller
    Joined: Jan 26, 2012
    Posts: 1,105


    Back in the day I ran three two barrels on my 302 Windsor, it always ran good and I did not have issues. I even had cruise control on it. ( with a four speed)
    Now I have two 390cfm Holley’s on the Boss 302 in the Comet. After a little tuning and jet changes the engines runs good, starts easy, and is responsive. Besides that they look Bitchen!
  22. Moriarity
    Joined: Apr 11, 2001
    Posts: 31,599

    Staff Member

    My 40 has 4 chrome 97's, not the new ones but old ones that I bought at swap meets and rebuilt myself. It took 7 swap meet chrome carbs to get enough good parts to build 4 carbs. this setup has been on my car about 10 years now and I have not hat to touch a single adjustment since. It runs great and idles as smooth as a gravy sandwich.

    40.....jpg 401.JPG

    My corvette has a Man A Fre 4 carb setup. 4 58 chev rochester 2 gc's. this car gets 17 mpg in a mix of around town and freeway driving . And goes like a scalded dog....
    vette4.JPG vette1.JPG
    Hemi Joel, Paul, olscrounger and 23 others like this.
  23. Blues4U
    Joined: Oct 1, 2015
    Posts: 7,589

    from So Cal

    Haha, that's awesome! Love it!
  24. Pete1
    Joined: Aug 23, 2004
    Posts: 2,258

    from Wa.

    I ran 4 floatless 48's on my vintage flathead powered circle track roadster for many years.
    I found 10 more hp with a set of mechanical Hilborn's and better throttle response.
  25. I’ve had several set ups on my Austin. Now running 3 1958 2Gs with progressive linkage. It took a little while to get them right but that was half the fun. Runs well, good mileage and not temperamental at all.
    A834F253-5E0E-473B-8C42-FF2414EC3895.jpeg 7710D4CD-84E0-42B1-9588-FABDD249B387.jpeg 6A1BE05C-71E3-4622-9263-E8B22C500B3D.jpeg B1E419B5-E7F8-41B9-BD9E-33D43016412D.jpeg
    Elcohaulic, X-cpe, 3W JOHN and 10 others like this.
  26. 2BD276B3-67DD-4001-B700-8CEA6AE55114.jpeg When I first built my 36 Ford I set the SBC up with dual 94s on one of those 4bbl adapter gizmos. It looked great and had good low end power and snappy throttle response but ran out of steam at upper rpms. It was soon replace by a 4bbl carb and it ran considerably better. (Please disregard the wheel/ tire combo,, it seemed like a good idea at the time, oh and the valve covers and wires also!!) It wasn’t a true multiple carb set up but that’s as close as I got. When I build the inline 250 for my pickup it will have at least 2 carbs and split exhaust. Mitch
    Last edited: May 23, 2021
  27. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,064

    Mike VV
    from SoCal

    Why wouldn't they be reliable ?
    I ran a Man-a Fre on a small Chevy for many years on the street. That same setup was run on a 265, a 327 and a 350, all in the same car.

    I've put this together for my 299 inch, 54 Stude powered Conestoga.
    Used to be a small Chevy intake manifold, now bolts on a Stude engine with the help of a set of adapter plates.


    3W JOHN, Tim, mgtstumpy and 7 others like this.
    Joined: Feb 21, 2010
    Posts: 375


    My 56 Chevy has a 383 SB Chevy with 550 Edelbrock dual 4bbl carbs. been running them for 14 years now and have been pretty trouble free actually. Also running a 348 with threee Rochester 2G carbs in a 59 Impala. Pretty trouble free. Both cars are 5-speed standard transmission cars.

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