Edelbrock 600 cfm Performer Secondaries

Engine, Transmission & Driveline

  1. ArnieJr

    ArnieJr New Member

    Messages:
    17
    Likes Received:
    0
    Joined:
    Nov 2, 2019
    Location:
    NC
    I'm just learning about carburetors, so my knowledge on the subject is limited. To borrow a phrase from Mr. Van Zandt, "I know a little bit".
    About two months ago, I purchased a 1969 Chrysler 300 with the base (K) 440 and aftermarket Edelbrock 600 CFM Performer 4 barrel (which I've learned is totally wrong for the car, but that's for another time).
    Of course, the 300 is a HEAVY car and not necessarily built for speed, but I'm not sure if the secondaries are kicking in. Is there a way to tell? I can see the linkage move with the engine off, but the secondaries won't open because the choke is closed ("I know little") with the motor off. I saw a YouTube video of someone slowly revving up a Mustang engine and showing the secondaries open. I am hesitant to try that for fear of damaging the engine.
    So any suggestions would be appreciated. The carb looks brand new and is advertised as the automotive equivalent of "plug n play" so I can't imagine that there's anything wrong with it or the installation (I didn't put it on).
     
  2. furious70

    furious70 Active Member

    Messages:
    444
    Likes Received:
    158
    Joined:
    Aug 18, 2018
    Location:
    Chitown
    Electric choke? Once warmed up is it opening up fully to release the linkage that prevents the secondaries from opening? Check that mechanical issue first.
    If that's ok then they are opening when you floor it since it's a mechanical vs vacuum secondaries
     
  3. detmatt

    detmatt Old Man with a Hat FCBO Gold Member

    Messages:
    23,888
    Likes Received:
    9958
    Joined:
    Nov 14, 2010
    On the contrary that carb is a relatively good choice for that car. Approximately the same cfm as the original carb and if working properly should provide good throttle response.
     
    • Agree Agree x 6
  4. Dsertdog

    Dsertdog Old man with an old guitar, and a blue note. FCBO Gold Member

    Messages:
    354
    Likes Received:
    403
    Joined:
    Feb 19, 2019
    Location:
    Oklahoma
    The part or list number would be helpful, but I agree the carb is plenty big for this application.

    The reason I asked about the part number, is that you may have an AVS carburetor, AVS meaning Air Valve Secondary. This device looks much like a choke, a flap above the secondaries. Your secondary butterflies are opened manually, but the air valve flap opens by engine demand, which is measured by vacuum. As the flaps open, air is drawn through venturis, pull a measured amount of fuel into the engine as it requires it. The only way the secondary butterflies would not open is if the the choke is mis-adjusted or not getting hot enough to disengage the secondary lockout.
    Like vacuum secondary holleys, you almost never see the valve open under no load acceleration, and if you did the engine would likely bog as they did because there is no accelerator pump to add gas when the vacuum dumps (gas pedal floored).
    I intentionally left this as basic as I could, for there is plenty of tuning information on the internet.
     
  5. furious70

    furious70 Active Member

    Messages:
    444
    Likes Received:
    158
    Joined:
    Aug 18, 2018
    Location:
    Chitown
    Avs would be a 650cfm. Guess it doesn't hurt to validate the PN of the carb.
     
  6. ArnieJr

    ArnieJr New Member

    Messages:
    17
    Likes Received:
    0
    Joined:
    Nov 2, 2019
    Location:
    NC
    It's a 1406, based on the NAPA part number on the box the seller had left with the car. I assumed it has mechanical secondaries, but can't find anything online to tell me definitely. Does AVS mean the same as vacuum?
    https://www.napaonline.com/en/p/BK_7353556
     
    • Thanks! Thanks! x 1
  7. Dsertdog

    Dsertdog Old man with an old guitar, and a blue note. FCBO Gold Member

    Messages:
    354
    Likes Received:
    403
    Joined:
    Feb 19, 2019
    Location:
    Oklahoma
    The 1406 is an AFB replacement carburetor. AFB (or Aluminum Four Barrel) is the predecessor to the AVS. A similar sized AFB would have been factory on your car.

    It is a mechanical secondary carburetor and there's no air valve, so it relies on the main pump squirt to cover the secondary opening.

    The only reason the secondaries will not open is either interference with the intake (not likely) or the electric choke is mal adjusted and the secondaries are locked in place. This feature is used to reduce engine wear and keep poor gas mileage from being an issue until engine warms up.

    Best way to check is run the engine up to operating temp and verify that the choke flap is straight vertical. Adjust choke as needed to make it correct. Most carbs are factory set very close. With the engine off, have helper floor the gas pedal and look down inside the carb to see if the secondaries open. If not your throttle linkage may need adjusting.
    There is also linkage on the carb to open the secondaries. While this can be adjusted, it shouldn't need to be done.

    A lot of great carburetor setting tips for the AFB can be found in a Chiltons or Factory Service Manual as well the Edelbrock site.
     
    Last edited: Jan 1, 2020
    • Like Like x 1
  8. furious70

    furious70 Active Member

    Messages:
    444
    Likes Received:
    158
    Joined:
    Aug 18, 2018
    Location:
    Chitown
    Should also be said that 1406's are set from the factory with a lean tune in them. My experience has been out of the box they generally castrate an engine. Use their set up for a manual choke carb, used to be on their website somewhere
     
  9. CBODY67

    CBODY67 Senior Member

    Messages:
    4,126
    Likes Received:
    964
    Joined:
    Mar 27, 2011
    The factory AFB that was on m y '67 Newport 383 4bbl is a manual-secondary carb. There's nothing between the secondary throttle plates and the top of the air cleaner. Some Chrysler OEM applications and most GM applications have a weighted "air valve" just above the secondary throttle plates, which open with air flow over them and through the secondary barrels of the carb. I believe the Performer AFBs are also this way, too? The only way to adjust the opening of these secondary air valves is by removing weight from their counterweights (not recommended, unless it's a full race engine under the carb). Kind of a mechanical way to get to what Holley did with their vacuum secondary system.

    If the choke is such that the fast idle cam is engaged, there is a link to prevent the secondaries from being actuated, which should be illustrated in either the FSM or an Edelbrock adjustment document (engine at operating temp and stopped).

    The Edelbrock 1406 is an "accepted change" from the OEM AFB or Holley 4bbl on Chrysler products. Just as the upgrade to a factory-style ('72 & up model year) electronic ignition is (as the prior Mopar Perf electronic ignition kit. It might not be a "numbers match" situation, but a carb that will work pretty well out of the box, as is.

    Do make sure the throttle cable is adjusted to let the carb get to WOT with the accel pedal. Engine at operating temp and "off", of course.

    I'll concur that if the linkages and such are adjusted correctly, the secondaries should operate "as designed" when needed. With a single snorkel air cleaner, you might not really hear them, though, but on a WOT kickdown at about 30mph (which should result in a downshift into 1st gear), they should be felt.

    You can download the Edelbrock installation instructions and such from the www.Edelbrock.com website. The Chrysler Master Tech series might have some information on the OEM AFB carbs, too, but probably in a model year prior to yours (www.MyMopar.com). There are some great carburetor books -- S-A Designs has one specifically on Carters, I believe, but for a better general understanding, the original HPBooks book on Holley Carbs is very good, as is their later book on Rochester carbs.

    Keep us posted on your progress.

    Happy New Year!
    CBORY67
     
  10. TxDon

    TxDon Active Member

    Messages:
    307
    Likes Received:
    263
    Joined:
    Apr 24, 2018
    Location:
    McKinney, TX
    If you have not already done so you should adjust both the throttle and the transmission kickdown linkage per the FSM. This will include verifying that you have full secondary opening and if not, adjusting the cable to provide it. Once that is done the kickdown linkage has to be adjusted to the throttle opening. I converted my 383 to a 1406 Edelbrock and found the linkage was way out of adjustment. Once corrected both secondary opening and trans kickdown work as intended.
     
    • Thanks! Thanks! x 1
  11. 70bigblockdodge

    70bigblockdodge Old Man with a Hat FCBO Gold Member

    Messages:
    11,660
    Likes Received:
    4788
    Joined:
    Jan 19, 2013
    Location:
    Avonmore Pa.
    A Eddy carb has weighted secondary air valve, butterfly valves above the secondaries that are held shut by a counterweight, they do not seal up tight allowing air to pass when secondary manual valves are opened, as air speed increases passed the weighted valves they are forced open to satisfy engine demand.
     
    • Thanks! Thanks! x 1