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Technical Edelbrock 1404 bogs on secondary kick-in

Discussion in 'Traditional Hot Rods' started by TudorTony, May 6, 2015.

  1. TudorTony
    Joined: Jun 2, 2013
    Posts: 201

    TudorTony
    Member
    from NJ

    I have the 1404 on a mild performance 8BA, 3/4 cam, oversize hardened valves, Red's headers, Offy heads. Car runs great on primaries but bogs and sputters on secondary kick-in. I have read this is a common problem with the Edelbrock 1404 and 1405 which is hard to remedy. Anyone been there and resolved?
     
  2. I'm running the 390 cfm on my 8ba, built sort of similar to yours with no issues at all. What cfm is the 1404? Also Edelbrock sends a book and CD for tuning them.
     
  3. TudorTony
    Joined: Jun 2, 2013
    Posts: 201

    TudorTony
    Member
    from NJ

  4. you will need to change the springs for the metering rods. Get a Edelbrock Calibration Kit for your model of carb. There are parts and instructions to help you along.
     
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  5. Drive'em
    Joined: Jan 7, 2013
    Posts: 255

    Drive'em
    Member

    Do what Boyd says.
     
  6. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,140

    gimpyshotrods
    Member

    Yup. Very tunable.

    It's only a common problem for people who can't, or won't tune.
     
  7. Andamo
    Joined: Jan 10, 2006
    Posts: 500

    Andamo
    Member

    The problem isn't the carb, but your cam. Whenever you get the other 1/4 of your cam, you'll be ok. lol
     
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  8. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,783

    Mike51Merc
    Member

    It's not the carb's fault. You're asking a 239 cubic inch low revving flathead engine to inhale 500 CFM. Just on the arithmetic alone, it just ain't gonna happen no matter how much cam and valve work you do. For example, 239 cubic inches at 5000 RPM is only 344 CFM at 100% efficiency.
    Like others said, you may be able to tune it better, but the 390 CFM has been to go-to carb for a lot of guys.
     
  9. gimpyshotrods
    Joined: May 20, 2009
    Posts: 16,140

    gimpyshotrods
    Member

    The front-half of the carburetor can be made to work fine. He just won't use the secondary side.
     
  10. TudorTony
    Joined: Jun 2, 2013
    Posts: 201

    TudorTony
    Member
    from NJ

    Mike51Merc, math seems right, never really thought of checking max possible cfm intake potential for the Flatty. I think it's approx 366 cfm for mine as I have a 4" bore with a Merc crank as well which puts it at 255 c.i., still too much. Don't mind tuning the 1404 but sounds like I can't get it to what it needs to be on a full dump cfm tromp. My 442 carb needs a to be rebuilt, maybe I'll use the 1404 on it and get a Holley 390 as indicated.
    Thx all for the inputs
     
  11. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,783

    Mike51Merc
    Member

    Tony,
    You also have to take volumetric efficiency (very poor in flatties) and RPMS (very low/poor in flatties) and then you begin to understand why Ford built them with 150 CFM carburetors.
     
  12. Lobucrod
    Joined: Mar 22, 2006
    Posts: 4,076

    Lobucrod
    Alliance Vendor

    Make sure the secondary air valve and weights were not left out. Lots of people leave them out thinking it will increase the flow.
     
  13. The Holley ain't gonna be much better. I'm running a 500 on the flatty in my avatar and the secondary works fine. As others have said, get the kit and play around with it a little. I used Holley for years and quite honestly wouldn't go back after having the Edelbrock (Carter AFB)
     
  14. oj
    Joined: Jul 27, 2008
    Posts: 6,110

    oj
    Member

    The carb size is by horse power, not size of engine. A 350" engine makeing 100hp will need a much smaller carb than a 350" making 500HP. Flatties got torque not HP, a smaller cfm carb will flow the same air at higher velcities and that will improve your torque.
    Edelbrock square bore carbs secondaries don't 'kick in' they are kinda smooth, you almost have to take it on faith they are working.
     
  15. Mike51Merc
    Joined: Dec 5, 2008
    Posts: 3,783

    Mike51Merc
    Member

    /
    Where did the horsepower come from? While what you say is generally true, horsepower comes from airflow, and airflow comes from the engine displacement (size) cycling through its revolutions per minute. More simply stated, a 350 cubic inch engine will flow 350 cubic inches (minus whatever losses for inefficencies) of air for every two rotations of the crankshaft. Carbs are measured in cubic feet per minute and an engines ability to intake is measured by cubic inches per revolution per minute, minus losses. The rest is just mathematics. The faster it spins, the more CFM it can handle. The more hp it has, the faster it can spin. The reason I'm saying all this is that when it comes to choosing a maximum carburetor size, it pays to know the maximum flow potential of your engine because no engine can flow more than its SIZE x RPMS/2 unless it has forced induction. Knowing the engine "has" (or is capable of) 100 or 500 horsepower cannot guide anyone to choosing a carburetor size. The cart (carburetor) has to come before the horse(power).

    A smaller carb increases intake velocity because the air is being sucked through a hole smaller than the engine is capable of pulling. Putting a larger carb reduces velocity. It's like trying to whistle with your mouth wide open.
     
    Last edited: May 8, 2015
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  16. Schwanke Engines
    Joined: Jun 12, 2014
    Posts: 782

    Schwanke Engines
    Member

    Never had much luck with Holley carbs in general unless it's a Willy's but they really aren't holley anymore. Edelbrocks always seem to work better for street applications. Just get the spring kit and play with it. That's what I'm running on my 286 flatty.
     
  17. TudorTony
    Joined: Jun 2, 2013
    Posts: 201

    TudorTony
    Member
    from NJ

    Went with my original set-up of Holley 94 2x2 direct linkage, seems to work fine with no bog when tromped.
    Thx for all the good advice
     
  18. Mike VV
    Joined: Sep 28, 2010
    Posts: 1,560

    Mike VV
    Member
    from SoCal

    While that carburetor CAN be made to work....the engine AND the driver would be much happier with the smaller (390cfm) carburetor.
    Just takes some tuning to make the 500cfm carb. work correctly. The as mentioned "carburetor kit" is required.

    Mike
     
  19. 36tudordeluxe
    Joined: Oct 2, 2008
    Posts: 496

    36tudordeluxe
    Member

    I have a 1404 on my 276 with L-100 and performs well through entire RPM range, try reference #11 in owner's manual. 276 left.jpg
     
    Chili Phil likes this.
  20. 36 coupe
    Joined: May 5, 2008
    Posts: 94

    36 coupe
    BANNED

    Did you try moving the accelerator pump linkage up to the top hole ?
    I had the same issue on a stock SBC and this fixed it.
     
    283john likes this.
  21. Blue One
    Joined: Feb 6, 2010
    Posts: 9,730

    Blue One
    ALLIANCE MEMBER
    from Alberta

    :D I've never understood why someone would install a partial cam :D And the carb isn't bogging, it's the engine :p
    You have some work to do to sort out this mess.
     
  22. TudorTony
    Joined: Jun 2, 2013
    Posts: 201

    TudorTony
    Member
    from NJ

    e4555ff2-7449-42c4-b3de-4e831018a3e0.png Very nice looking motor 36tudordelux, especially like the black intake against the chrome and polish! While I pulled the 1404 off for now and am running an older twin two barrel 94's set up for now, in the event I try it again I will check the note 11 in manual, also will check on the hole the accelerator pump linage is set 36 coupe. For now I put the 1404 on my 442 and it runs great as is on that vehicle and is much nicer looking. Had a double pumper Holley 650 which really didn't make any sense as it was pretty old and ugly and I really don't race / pound the 442 anymore ( used to as a kid, 65 now and more mellow, LOL ) ). I don't even notice the difference with the 150 less cfm rating.
     

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