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carb spacers????

Discussion in 'The Hokey Ass Message Board' started by detroitboy27, Oct 30, 2012.

  1. detroitboy27
    Joined: Oct 30, 2008
    Posts: 108

    from katy, tx

    I have searched other forums and this one, and would like to get some opinions.

    I'm currently running a stock L79 corvette 327. Lake style headers and an open hood. I would really like to get a tunnel ram dual quad set up, but from what I've read on this forum and others that it would be overkill for my motor.

    I was thinking of running the edelbrock dual quad setup, and them putting 2 in spacers on it to give it a more aggressive look. Are there any pros and cons to doing this, there are different types of spacers out there, what would you guys recommend. Or am I just nuts going after a "look"?

    Thanks in advance
  2. 57countrysedan
    Joined: Oct 28, 2012
    Posts: 370

    from NY

    Think summit had a good article of pros and cons to spacers. Also wat types make wat type of power. Search their tech help thingy

    Posted from the TJJ App for iPhone & iPad
    Joined: Jul 16, 2006
    Posts: 2,571


    Wood works great.

    Use a hi grade plywood.
  4. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 31,551

    Jalopy Joker

    don't know about 2" spacers but, the aluminum 4 hole 1" spacers with swirl marks in them make a good difference in adding bottom end performance.
    Last edited: Oct 30, 2012

  5. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,065

    Mike VV
    from SoCal

    Seems there are some wives tales among us..!

    In a proverbial nutshell...spacers will fool the engine into thinking there is a larger carburetor on it thAn actually is. The open or the four hole spacer add to the Plenum size.

    An open spacer, while increasing the plenum size the most (think larger carb.), it will also slow down the fuel charge so that it will make the turn from the plenum to the runner easier at higher speeds thAn the four hole. Though at low to moderate speeds, the four hole will increase the throttle response over the open version.
    So, four hole works better for throttle response, open works better for higher rpm power. The manifold design just under the carb. gasket makes some difference in the way either work also.

    And yes, the phenolic spacers do a good job if insulating the engine/manifold heat from getting to the carburetor. Not perfect, but do help.

    Then there are the combination style. These start out as a four hole on the carb. side, but have been countoured/blended on the manifold side to be open...and smoother flowing.
    BUT...they don't come cheap..!

    If I were you...I'd buy both (open and four hole for each carb.!), and give both sets a try on "your" particular setup. While in "general" what I noted above is true, each engine and its combination of cam, carb. size and intake manifold all play a part in how a spacer will work.

  6. This is your answer but not in "typical" plywood.

    AED makes a great spacer out of Birchwood. The Birchwood spacer has better thermal barrier protection than your traditional aluminum spacer and unlike the plastic spacers, will not distort. I got 9 extra "dyno proven" horse out of my 408 sbc with the 1/2" AED spacer.

    Now if you were going for the ultimate in gain, the Wilson Manifolds tapered 4 hole 2" spacer gave me 30 extra horse on the dyno.

    Here is a link to AED and their spacers:

    Good luck!
  7. detroitboy27
    Joined: Oct 30, 2008
    Posts: 108

    from katy, tx

    thanks for the answers
  8. Blacktop VooDoo
    Joined: Oct 28, 2011
    Posts: 130

    Blacktop VooDoo

    If you are a tunnel ram fan, fear not. I had a T Bucket with a 283 sbc, mild solid cam with a tunnel ram and two holley 390's fitted with #51 jets. It actually performed very well!!
  9. look. Are there any pros and cons to doing this, there are different types of spacers out there, what would you guys recommend.
    Take a look at Dashman H.A.M.B. alliance vendor
  10. dashman
    Joined: Apr 15, 2009
    Posts: 774

    from Viroqua WI

    I have yet to have an engine not respond positively to a spacer, especially vintage manifolds that were relatively flat to begin with.

    These days with the poor gasoline an insulator is a must, I prefer phenolic. A 1/4" phenolic riser will cure about any heat soak problem. If a lot has been modified from stock, fans, low engine, or like a huge air cleaner that acts like a heat sink, a 1/2" thick one might be better.

    1" and up aluminum carburetor risers work, period. Too tall can be a problem, but most guys that run too big of a carb try to make it better with a 4" riser, it won't work.

    Any engine that is modified will benefit. There are some really fancy risers out there and will produce results, but often you will have to dyno tune that engine to see the full benefit of that particular riser. It might not be worth the extra money unless you have the dyno time.

    We typically see an average of 15 HP on a riser, a cheap price to pay for that kind of performance.

    Dashman's Hot Rod & Speed Parts

    Attached Files:

  11. Blues4U likes this.
  12. Aducati4me
    Joined: Nov 24, 2017
    Posts: 10


    Dashman, sorry I know this is an old thread but what’s your thoughts on a 2” riser with an adapter on top to go from large base to small base Rochester 2G tri-power on a modified 409? Is 2” too much? It would end up being about 3”of rise.

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