Holley Street Avenger 670cfm to big for 318cui?

Small Block Mopar Engine

  1. KingGermanFool

    KingGermanFool Member

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    Hi,

    i have bought some new parts for my stock 1969 Plymouth Barracuda, 318 small block with 4 speed manual.

    I read the following article:
    https://www.streetmusclemag.com/news/common-upgrades-for-an-la318-in-a-1971-dodge-dart-swinger/

    Therefore, I decided to also buy the 670cfm Holley Street Avenger.

    After searching some more information I am now unsure about the decision.

    Is this carburetor too big for my 318?

    I have bought the carburetor at Summit. Should I send it back and get a smaller one?
    Which one would you recommend for my setup?


    This is the list of parts what I have bought:

    Carburetor:
    Holley 0-81670 - Holley Street Avenger Carburetor
    (670 cfm, Square Bore, 4-Barrel, Vacuum, Manual Choke, Dual Inlet, Silver, Each)

    Intake Manifold:
    Weiand Intake Manifold 8022WND Stealth Aluminum

    Valve Covers:
    Mopar Performance P5007613AB Valve Covers

    Air Cleaner:
    Holley 120-153 - Holley Vintage Series Air Cleaner

    Ignigtion:
    MSD Ignition 6425 - MSD Digital 6AL Ignition Controller
    MSD Ignition 8203 - MSD Blaster 2 Ignition Coil
    MSD Ignition 85551 - MSD Pro-Billet Distributor


    Thank You
    Greetings from Germany
     
  2. Lelo Dart

    Lelo Dart * FABO Gold Member

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    No, it should be fine. My 318 really liked the 570 Holley but it will run fine with the 670. I now run the 670 on a 5.9 which runs well but tried an 870 and it ran just as fast but was less responsive on the street and was fouling plugs.
     
  3. 66fs

    66fs FABO Gold Member FABO Gold Member

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    I've run a 750 cfm TQ on a 273, As long as the fuel mixture is good, I would not worry about it. I see you have a 4 speed that should help.
     
  4. rumblefish360

    rumblefish360 So close, yet so far away FABO Gold Member

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    Keep it and run it. Once you spend a little time tuning it so it doesn’t run rich or lean, it’ll be just fine.
     
  5. mopowers

    mopowers Well-Known Member

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    An interesting note about those 670 SA's - They have the same venturi and throttle bore diameters as a regular old 3310, which Holley rates at 750 cfm. Not sure how they come up with these ratings.
     
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    • KingGermanFool

      KingGermanFool Member

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      Thank you guys for your feedback!
      I'll keep the 670cfm.


      Now I have another question wich may is not worth an extra thread.
      I have bought a "Weiand Intake Manifold 8022WND Stealth Aluminum".
      Weiand 8022WND Weiand Stealth™ Intake - Chrysler Small Block V8

      In the desciripion it is stated to fit for 318 - late style.
      What does that mean? Will it fit my 1969? Or do I need another intake manifold?
       
    • 318willrun

      318willrun Utube channel 318willrun

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      Carb will work just fine. Intake will work, I think they mean LA style.
       
    • Mattax

      Mattax Just the facts, ma'am FABO Gold Member

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      The area you may have difficulty with is the carb's circuit calibration.
      If so, as long as you are willing to spend the time and energy, it can be recalibrated with some home shop work.

      In my opinion potentially the MSD 6AL and distributor are going to be the bigger headaches.
      Some of that is luck of the draw (quality)
      The rest depends on what has been done to the engine.

      If its a stock engine the issues will be:
      The carb is likely to be rich at idle and take some effort to tune for good low speed.
      Its going to be rich because it will have strong manifold vacuum. (Low MAP) with a stock cam etc.

      The distributor issue will mostly be the advance curve. Chrysler engines like the two stage advance and the MSD distributors advances are really not good for creating an advance curve shaped like that.

      my twocents-gif.gif
       
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      • mopowers

        mopowers Well-Known Member

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        Just curious - if not the 6AL, what ignition do you recommend?
         
      • Mattax

        Mattax Just the facts, ma'am FABO Gold Member

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        Assuming its a stock '69 2 bbl 318 ?
        Going to a four barrel, probably a Pertronix in factory single point distributor set up with a curve similar to '67 273 4 bbl.
        But if the 6AL works, I'd use that with a single point distributor set up with a curve similar to '67 273 4 bbl.

        I think the difference between the kettering and the multispark ignition in terms of producing a good burn are going to be too small to notice here. So then its just a matter of reliability. And it seems that nothing aftermarket has been really bulletproof in recent years. :(
         
      • Ricks70Duster340

        Ricks70Duster340 Child of the King, widower FABO Gold Member

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        The "early style" 318 was the poly. Their choice of words is poor. They should have said that it fits all "LA" engines. They mentioned the 340 & 360, which were both "LA". LA simply means "lightweight A".
         
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        • sireland67

          sireland67 FABO Gold Member FABO Gold Member

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          I think you will be fine, the street avengers tend to run alot leaner than other similar sized carbs.
           
        • Bewy

          Bewy Well-Known Member

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          I will disagree with the other opinions & suggest you swap the Holley for an Edel AVS2 carb.
          My reasons?
          - main reason is that although both carbs have similar cfm ratings, the Edel has smaller primaries [ secondaries are larger to give the total of 650 cfm]. Smaller primaries, all else being equal, give better response/feel. With the H carb, all four bores are the same size. Plus, the Edel has annular boosters in the primaries. The combination of the smaller pri bores AND the ann boosters will give better throttle response on the primaries, where most driving is done. Fuel economy should also be better.
          - the engine is stock. So a carb that 'livens up' an otherwise stock, low power engine will make you feel like the expense of a new carb was worth it.........
           
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          • Ricks70Duster340

            Ricks70Duster340 Child of the King, widower FABO Gold Member

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            I just replaced my Street Avenger 670 with an AVS2 650. Yes, the low speed throttle response is a little better, but not significant. Fuel economy should be better because unlike the Holley, the AVS2 only opens the secondaries at near WOT. Either one should be fine. The AVS2 comes with a 3/8" fuel inlet nipple, so I had to take the nipple off of my original AVS and put it onto the new carb because my stock fuel line is 5/16". Basic tuning of the new carb was simple. Bought the jet kit but don't need it for my basically stock engine.
             
          • racerdan80

            racerdan80 Well-Known Member

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            Keep the 670 and tune it. I run that on my 68 318 with the stock cam and headers. Ran real good after just tuning to what the motor wanted
             
          • 318willrun

            318willrun Utube channel 318willrun

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            Personally, I prefer 1200 cfms on my 318...... hooked direct, 1 to 1 :)

            :poke:
            :poke:
             
          • rumblefish360

            rumblefish360 So close, yet so far away FABO Gold Member

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            Note, that intake has no provisions to mount a coil.
             
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