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Hot Rods 3x2 setup on a 671 Blower

Discussion in 'The Hokey Ass Message Board' started by Bonehead II, Mar 31, 2020.

  1. Bonehead II
    Joined: Apr 18, 2005
    Posts: 383

    Bonehead II
    Member

    Hey Guys..I have a 3x2 setup with small base Rochester carbs, that I want to put on a 671 Detroit blower, I was told by a guy that I would starve the front and rear cylinders of fuel. also I would like to use a progressive linkage. This is only for the street use.
    Please let my know what you think.
    Thanks
     
  2. Jmountainjr
    Joined: Dec 29, 2006
    Posts: 944

    Jmountainjr
    ALLIANCE MEMBER

    Before diving in, I would think through some technical issues:
    The vaccum operated power piston will see constant vacuum from being on top of the blower. There are ways to modify a carb to see manifold vacuum. It's called boost referencing. Not sure how to do it on your carb.
    Do some research on fuel total requirements. If your tri power set doesn't have idle circuits in the end carbs you might have some tuning issues.
    The tri power on a blower has been around for a long time, but usually with different carb choices. Hope you get it all worked out and let us know.
     
    Last edited: Mar 31, 2020
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  3. ^What is said above^. Also, progressive linkage, no. Diving around on one two barrel is not going to feed a 671 equipped engine. Research blower threads and read lots of info.
     
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  4. squirrel
    Joined: Sep 23, 2004
    Posts: 45,182

    squirrel
    Member

    I put over 100k on a progressive linkage dual quad holley setup on a blower....it works fine....you'd be amazed how well it blends. And I doubt it's going to need boost reference, because it won't make much boost without letting in much air, because....

    The big problem I see is that three deuces is about half the CFM you need on a 6-71. Maybe if you could squeeze 6 or 8 of them on there, you might have something.
     
    Last edited: Mar 31, 2020
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  5. DOCTOR SATAN
    Joined: Mar 21, 2014
    Posts: 711

    DOCTOR SATAN
    Member
    from okc

    Now we're talkin'.....
     
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  6. Mat Thrasher
    Joined: Nov 5, 2007
    Posts: 1,106

    Mat Thrasher
    Member

    Here's my 6x2 set up that I run a progressive linkage on. The front two driver's side carbs are the primary carbs. It's an 8-71 on a 582 BBC, the carbs are large base Rochester 2g's.

    It's runs great on the street and the track. I never had any issues with any cylinders running lean.
     

    Attached Files:

  7. Bonehead II
    Joined: Apr 18, 2005
    Posts: 383

    Bonehead II
    Member

    OK..then what size of Holley carb's should I be looking for, remember street only.
    Thanks
     
  8. DDDenny
    Joined: Feb 6, 2015
    Posts: 13,194

    DDDenny
    Member
    from oregon

    Are we supposed to guess what engine you plan on putting this setup on?
    Size matters!
    Engine size that is.
     
  9. squirrel
    Joined: Sep 23, 2004
    Posts: 45,182

    squirrel
    Member

    500 to 750 depending on the size of the engine.
     
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  10. Seriously??? I know it won't be long before Google can read your thoughts and predict the futures, but we aren't there yet.

    Tell us about the engine combo. Big difference in carb requirements between bolting that 6-71 to the side of a 300 I6 or on top of a 460 punched and stroked to 600 ci.

    [​IMG]
     
    Last edited: Apr 1, 2020
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  11. Jack E/NJ
    Joined: Mar 5, 2011
    Posts: 575

    Jack E/NJ
    Member
    from NJ

    >>>I have a 3x2 setup with small base Rochester carbs, that I want to put on a 671 Detroit blower>>>

    More likely a 350. 8^) Jack E/NJ
     
  12. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 24,593

    Jalopy Joker
    Member

    why try to run 3x2 set with blower?
     
  13. Bonehead II
    Joined: Apr 18, 2005
    Posts: 383

    Bonehead II
    Member

    Sorry guys...I feel like a dum ass....its a 350 with a 383 forged crank, rods, & pistons...30 over...Edelbrock 70cc chamber heads,
    671 Detroit blower converted and rebuilt for gas.
     
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  14. Bonehead II
    Joined: Apr 18, 2005
    Posts: 383

    Bonehead II
    Member

    I like the old school look
     
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  15. squirrel
    Joined: Sep 23, 2004
    Posts: 45,182

    squirrel
    Member

    When was three rochester 2bbls on top of a 6-71 ever a look?

    Just curious.
     
  16. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 24,593

    Jalopy Joker
    Member

    so, do you have any pictures of "old school" 3x2 / 671 to share here?
     
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  17. Bonehead II
    Joined: Apr 18, 2005
    Posts: 383

    Bonehead II
    Member

    sorry I don't I just like the look of 3x2 set up.
     
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  18. Boneyard51
    Joined: Dec 10, 2017
    Posts: 3,776

    Boneyard51
    Member

    I don’t know anything about blowers, but I like 3x2s also! Sometimes it’s about what you want.....not necessarily what you need!






    Bones 2A36F931-12C9-4E50-AD5C-33A5199CC58E.jpeg
     
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  19. Jack E/NJ
    Joined: Mar 5, 2011
    Posts: 575

    Jack E/NJ
    Member
    from NJ

  20. Could always go with 3 AFB's like this guy. I talked to him at a show several years ago and he drives it all over the place.
    IMG_0442.JPG
     
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  21. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,457

    Blues4U
    Member
    from So Cal

  22. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,457

    Blues4U
    Member
    from So Cal

    There's this one in the Induction thread:
    [​IMG]
     
  23. Blues4U
    Joined: Oct 1, 2015
    Posts: 4,457

    Blues4U
    Member
    from So Cal

  24. Bonehead II
    Joined: Apr 18, 2005
    Posts: 383

    Bonehead II
    Member

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  25. Bonehead II
    Joined: Apr 18, 2005
    Posts: 383

    Bonehead II
    Member

    If there is anyone out there running 3x2 carbs on a 671 street blower, would you please tell me what your running for carbs and what kind of CFM you have.....Thanks
     
  26. Jack E/NJ
    Joined: Mar 5, 2011
    Posts: 575

    Jack E/NJ
    Member
    from NJ

    Just use the ones you already got first. Jack E/NJ
     
  27. flamedabone
    Joined: Aug 3, 2001
    Posts: 4,648

    flamedabone
    ALLIANCE MEMBER

    For comparison, my 389 inch Pontiac with a 6-71 has two 750 cfm carbs. I started with two 600s, but the dyno proved them too small. To make boost, blowers need to draw free air through the suction side and three small cfm carbs may be too much of a restriction. They may also not be able to supply enough fuel, but only an air/fuel sensor can tell you for sure.

    What are the cfm ratings of the carbs?

    -Abone.
     
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  28. flamedabone
    Joined: Aug 3, 2001
    Posts: 4,648

    flamedabone
    ALLIANCE MEMBER

    I did a quick HAMB search and it appears Holley 94s are about 185 cfm. If so, three of them might be OK on an unblown small block, but adding a supercharger will be dicey. A huge key to a blown engines lifespan is fuel delivery.

    Another option is to hang six of those suckers on there like Thrashers ride. Plenty of cfm and it looks kick ass.

    -Abone.
     
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  29. sdluck
    Joined: Sep 19, 2006
    Posts: 2,337

    sdluck
    Member

    My buddies 32 ford glass car we built has a 406 chevie with a tk 500 trans and 4:11 gears has twin 750 holley blower carbs on a 8:71 runs excellent ,it is a street car,good gas mileage.I drove it from san jose to Pleasanton a few times
     
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  30. Jack E/NJ
    Joined: Mar 5, 2011
    Posts: 575

    Jack E/NJ
    Member
    from NJ

    2Gs ranged from about 250 to 450. Jack E/NJ
     
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