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Holley 670 truck avenger Carb

Discussion in 'Early CJ5 and CJ6 Tech' started by 1fastsedan, Sep 1, 2010.

  1. Sep 1, 2010
    1fastsedan

    1fastsedan Member

    Orange, CA
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    anyone use this carb? i got with my jeep. it needs a rebuild but i think it might work well. i was using the edelbrock performer before and had some issues with stalling but it was also running extremely rich. its seems the 670 might be a bit much for my 305.
     
    1fastsedan, Sep 1, 2010
    #1
  2. Sep 1, 2010
    eddiememphis

    eddiememphis Knuckle Buster

    Colorado
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    Jun 3, 2010
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    My buddy bought one for his '79 Bronco with a 351m. It's currently for sale on C-list. He found it impossible to tune. Holley's website says not for street trucks or towing. He put a 600 cfm vacuum secondary on it and it works fine.
     
    eddiememphis, Sep 1, 2010
    #2
  3. Sep 1, 2010
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    I and other ran (run) the TA470 with good luck. I do think the 670 would be too big for a 305.
     
    Warloch, Sep 1, 2010
    #3
  4. Sep 1, 2010
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Huh? Impossible to tune? They are quite tuneable. The 670 may or may not have been too big but with the right jets, etc. they are one one of the best aftermarket off road carbs out there. I prefer the Quadrajet myself but the TA is a very good off road carb. If you want it for pure hp then there are better ways to go.
     
    nickmil, Sep 1, 2010
    #4
  5. Sep 1, 2010
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    :iagree:
     
    nickmil, Sep 1, 2010
    #5
  6. Sep 1, 2010
    colojeepguy

    colojeepguy Colorado Springs

    At the foot of...
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    I'm running the TA 470 on my :v6:. I agree with the others that a 670 is a little big for a 305, but I think being at sea level you could probably jet it down & it would be OK.
     
    colojeepguy, Sep 1, 2010
    #6
  7. Sep 2, 2010
    Corveeper

    Corveeper Member

    Chanute, Kansas
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    Jul 29, 2005
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    With a redline of, say, 5500 RPM a 305 cid engine is going to move 485.4 CFM of air (engine displacement X peak RPM’s / 3456) assuming 100% Volumetric Efficiency, which it won’t do. It’ll get more like 80% VE.
    Is the Truck Avenger 470 a vacuum secondary 4 barrel like the 670 and 770? Sounds like that’s closer to what you need.
     
    Corveeper, Sep 2, 2010
    #7
  8. Sep 2, 2010
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    I know the 470 is vacuum secondaries, but I thought all the TAs were vacuum secondaries.
     
    Warloch, Sep 2, 2010
    #8
  9. Sep 2, 2010
    1fastsedan

    1fastsedan Member

    Orange, CA
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    Aug 18, 2009
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    pulling some numbers on my engine it looks like it produces 255 hp and 290 torque. would jetting down the 670 carb make it more desirable?
     
    1fastsedan, Sep 2, 2010
    #9
  10. Sep 2, 2010
    Warloch

    Warloch Did you say Flattie??? Staff Member

    Falcon, CO
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    I think it would take more than just jets. Pump, squirter, cam, plus secondary settings (spring) etc.

    You might give Holley's tech line a try and see if someone will point you in the right direction.
     
    Warloch, Sep 2, 2010
    #10
  11. Sep 2, 2010
    Corveeper

    Corveeper Member

    Chanute, Kansas
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    I believe that is correct.
    I was more wondering if the 470 is a four-barrel or a two-barrel. Sounds like it’s a four-barrel.
    Thanks.
     
    Corveeper, Sep 2, 2010
    #11
  12. Sep 3, 2010
    Dummy

    Dummy I kick hippies

    Escondido, CA
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    Dec 5, 2004
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    What he said.

    I've run 'em all (literally) and the Q-Jet is best, followed by the Truck Avenger. I ran a 670cfm Truck Avenger on my Chrysler 318. It had the very good 302 closed chamber heads, a small cam, and a Performer. VE I'm sure was better than pedestrian 305, but on par or worse than a 305 with modified Vortec heads and a similar intake.

    I'd say if you've already got the 670 run it. It'll be okay out of the box, but if you've got the jets you could sep 'em down a size or two on the primary and maybe 2 or 3 sized on the secondary. I'd say the spring is probably fine as is. Maybe upgrade the manifold if you're running a factory cast-iron jobbie (swap meet/craigslist SBC aluminum intake can be had for $50-$80). Otherwise, enjoy.
     
    Dummy, Sep 3, 2010
    #12
  13. Sep 7, 2010
    1fastsedan

    1fastsedan Member

    Orange, CA
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    i just got the rebuild kit today, i will contact holley and see what jets would work best. i will be running the edelbrock performer manifold. my issue is i cant find a used one for the vortec heads! looks like i will have to get one new.
     
    1fastsedan, Sep 7, 2010
    #13
  14. Sep 7, 2010
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
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    The thing about running a too-big carb is that you lose too much air velocity when you dump those big bores wide open and then the engine bogs until it can recover. I don't pretend to understand all of the physics behind this, but I can tell you that a smaller carb will always have a better throttle response than a larger one. The only real benefit from running a huge carb is realized at WOT at high RPMs where the big carb can pass more total air than a smaller one.

    That big 850CFM Holley double-pumper looked impressive as hell on my BB Buick (and later BB Chevy) drag car, but the 780 CFM vacuum secondary carb outran it any day of the week! A wise old racer once told me that if I couldn't decide between two carbs, go with the smaller one and you'll never go wrong. ;)
     
    w3srl, Sep 7, 2010
    #14
  15. Sep 7, 2010
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    So it's all in the Offenhauser intake I put on, not the carb?
    The 500cfm Perfomer on the Offy is far and above better than the stock 2bbl./ 2gc. Throttle response, driveability, overall power, and fuel mileage. And yes, the 2G was jetted and adjusted properly.

    Let me edit- The primaries on the 4bbl. are smaller than the venturis on the 2bbl. So I guess there's the key.
     
    Patrick, Sep 7, 2010
    #15
  16. Sep 7, 2010
    hopp

    hopp On our way....

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    Like W3SRL said velocity. It supports turbulence and better mixing.

    You don't want turbulence on the exhaust path but on the intake any mixing help improves combustion. IANA expert but that's my $.02.

    /Physics!
    //Chemistry!
     
    hopp, Sep 7, 2010
    #16
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