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Hot Rods I want a real definition between 2 barrel carbs and 4 barrel carbs

Discussion in 'The Hokey Ass Message Board' started by CokeandSmoke, May 22, 2018.

  1. CokeandSmoke
    Joined: Mar 21, 2018
    Posts: 12


    I want a real solid answer between the two. One that will go down in history! My uncle says the small blocks don’t need em so what?!
  2. Torana68
    Joined: Jan 28, 2008
    Posts: 1,138

    from Australia

    If you happy with a low HP engine stick with the two barrel, so no , v8 engines don’t “need” one or more 4 barrels. Now if you want more HP you do “need” one or more 4 or maybe multiple 2’s
    OahuEli likes this.
  3. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,929


    He's right.

    Only biological entities have needs.

    Inanimate objects don't.
    sko_ford, Squablow, blowby and 5 others like this.
  4. squirrel
    Joined: Sep 23, 2004
    Posts: 45,280


    your uncle ain't a hot rodder, so don't listen to his car advice
    verno30, R A Wrench, OahuEli and 10 others like this.
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  5. Your uncle is right.
    You two should define "need"

    Now,,,,, the engine lives a better life worth living with more air and more fuel
    '51 Norm and loudbang like this.
  6. Squirrel is Correct!

    To add to what 31 Vicky with a Hemi said. Once you mount the more air and more fuel system, in order to make them work the best they can you must add a different Cam profile and a better set of Heads. Pretty soon you'll have a real Hot Rod.

    Your Uncle may be right about the Motor and it's needs. Generally it's the Driver that has the Need.
    The Wizzard
    Spooky and loudbang like this.
  7. Deuces
    Joined: Nov 3, 2009
    Posts: 18,415

    from Michigan

    232144-1288659372-5e83f33ae6a9127adccbdb1fd083dd00.jpg What other reason do you need????....
    Spooky, OahuEli, CAHotRodBoy and 4 others like this.
  8. Mike VV
    Joined: Sep 28, 2010
    Posts: 1,803

    Mike VV
    from SoCal

    Coke wrote -
    My uncle says the small blocks don’t need em so what?!

    Yeaa...exactly WHAT doesn't a small block NEED, please clarify ? What's "em" stand for ?

    If you are talking a four barrel carburetor, what has been written above is pretty much correct.

    loudbang likes this.
  9. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,208

    from oregon

    What was the question?
    czuch likes this.
  10. Rickybop
    Joined: May 23, 2008
    Posts: 6,276

    from Michigan

    verno30, 55Deso, dan31 and 6 others like this.
  11. Well, there's something to be said about efficiency...

    I do know that a typical mid-'70s lo-po 350 Chevy with a factory 2V could show a real improvement in fuel economy by switching to a 600 CFM vacuum-secondary Holley, as well as gaining power at the top end. The two barrel was a compromise; it had to be big enough so the motor wasn't badly starved at high RPM, yet was too big at low speeds as velocity through the carb was too low for the best fuel atomization. The smaller primaries on the 4V would usually gain you 1-1.5 MPG with no other changes.

    Those 500 CFM 2V Holleys were real dogs on the street. MPG in the low 10s or less around town wasn't unknown.
    Nailhead A-V8 and cavman like this.
  12. pontman
    Joined: Mar 18, 2011
    Posts: 393


    My advice is don't listen to your uncle.
    hrm2k, tractorguy and bobss396 like this.
  13. southcross2631
    Joined: Jan 20, 2013
    Posts: 3,533


    GM spent millions on testing and if a 2 barrel was enough then then why did put 2- 4 barrels on a small block. Tell your uncle that opinions are like assholes, everybody has one.
    tractorguy and Deuces like this.
  14. i wonder if he/you misunderstood the question/answer. could he have been arguing over the need for two four barrel carbs? or multiple carbs versus one big four barrel?
    Saxon, Hnstray and Just Gary like this.
    Joined: Dec 14, 2009
    Posts: 2,232


    Does it need it? No.
    Does it want it? Yes.

    Kinda like asking , do I need that 5th beer? No, do I want it? YES !!
    OahuEli, lothiandon1940 and '51 Norm like this.
  16. 62rebel
    Joined: Sep 1, 2008
    Posts: 2,740


    funny how the title of the thread implies one question and the content of the thread implies another. Going by the title, a 2 barrel carb has two venturi; and a four barrel has four. Going by the content of the first post; an engine needs whatever it takes to get the job done for which it is intended. If you're putting around in a grocery-getter sedan, never going over the in-town limit, two barrels will do you just fine. If you're looking for getting from, say, Bakersfield to Hemet in a couple of hours, you might want a couple of fours and the requisite manifolding and cam work....
    LM14 and Hnstray like this.
  17. wicarnut
    Joined: Oct 29, 2009
    Posts: 3,468


    Need/Want, Who's on First ?
    tractorguy likes this.
  18. Hundreds of millions upon millions of miles - trouble free miles using a 2 Barrel carb. Many of those miles at far above the legal speed limits
    tractorguy and Blues4U like this.
  19. carbking
    Joined: Dec 20, 2008
    Posts: 2,716


    Not certain I understand what is being asked. Does the OP wish to know if a small block Chevy needs a four barrel, or does he wish a treatise on the difference between two barrel and four barrel carbs?

    Just for the record, two barrel carbs have been used on some fairly good sized engines (one on a 1792 CID V-12).

    And a single barrel (that is correct, a one barrel) was used on a 5053 CID 8 cylinder.

    Often, progressive carburetors (virtually all four barrels) are used on engines with a wide RPM range to optimize engine efficiency over the range. Which is why some of the screamer 4-banger in the 1970's and 1980's used progressive two barrel carbs, even though sufficient air flow was easily obtainable with a one barrel.

    Have converted MANY engines (for street use) to more carburetion ALWAYS with an improvement in fuel economy as well as power (well, the fuel economy would depend on the driving habits of the operator).

  20. We might as well make this thread interesting.

    Why are 2bbl carb CFM measured differently the 4bbl carb CFM?
    And what's the conversion factors to get a true apples to apples comparison.
  21. flynbrian48
    Joined: Mar 10, 2008
    Posts: 6,356


    Wants are different from needs. Tell your uncle. IMG_3498.JPG
    loudbang likes this.
  22. carbking
    Joined: Dec 20, 2008
    Posts: 2,716


  23. I may not need a bigger penis.
    Frankie47, redo32, Just Gary and 2 others like this.
  24. The Shift Wizard
    Joined: Jan 10, 2017
    Posts: 1,881

    The Shift Wizard

    Most years I can think of, back before F/I, car manufacturer's V8 offerings could be equipped with either a 2 barrel or a 4 barrel set up. If City Hall went to the dealer to purchase a couple of 4-doors and one was for the police department, it "needed" a 4 barrel. And if the other was for the water meter reader department, it "needed" a 2 barrel.
    loudbang likes this.
  25. Get far away from that uncle....... you don't need that negativity in your life
  26. Paul
    Joined: Aug 29, 2002
    Posts: 14,641


    your uncle says small blocks don't need carburetors?
    he may have a point..
  27. Deuces
    Joined: Nov 3, 2009
    Posts: 18,415

    from Michigan

    Yep! They look better with injector stacks.... All 8 of them.....
  28. B.A.KING
    Joined: Apr 6, 2005
    Posts: 3,614


    Well, think about this, sometimes the factory even put 3 2bbl carbs on a engine......................................
    Ask ole unk about this..........................
    loudbang likes this.
  29. Go find a Stromberg PD-18 (generally attached to the inlet of the supercharger on Series 68 and 69 Rolls Royce Merlin V12's and Packard V-1650 engines). 2 Barrels of updraft fun. They can be identified by the 5 7/16" throttle bore. That's right, the throttle plates are considerably bigger then the piston bore on any small block.

    2 or 4 (or 3 or 1 or 6 or 8) barrels on a carburetor is meaningless without the context of the engine it is used on. The carbs job is to meter fuel and air. How it does that and its construction are defined by the OEM design engineer. Most of the time, cost is the primary consideration, with performance following behind. And when Holley or Carter or Rochester are using most of the same parts to build a 2 bbl or a 4 bbl, the OEM will take the 2 bbl every time on a lower cost model.

    loudbang likes this.
  30. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,208

    from oregon

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