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What are these holes all about???

Discussion in 'The Hokey Ass Message Board' started by Fat Hack, Nov 13, 2007.

  1. Fat Hack
    Joined: Nov 30, 2002
    Posts: 7,709

    Fat Hack
    from Detroit

    Okay, I know the four BIGGER holes are for the throttle plates, folks...but what about the two smaller holes on each side of them (next to the four throttle holes)??

    The intake is from a 1960s small block Chevy, likely topped with either a Carter or a 4-jet originally.

    Should these holes be plugged to run an Edelbrock??

    I've never had one of these old cast iron intakes before, so it's new stuff to me!!!

    Attached Files:

  2. Looks like a spot for the heat riser tube to be inserted.
  3. squirrel
    Joined: Sep 23, 2004
    Posts: 48,299


    Close, they are for the heat passages...the carb has a cast iron base, with a passage that runs around the front connecting the two side holes. Takes a special base gasket. You could plug them if you don't run the original carb.
  4. Allows hot air from the exhaust x-over to heat the bottom of the carb area for quicker warmups/better atomization of fuel in cold climates. Plug for "performance" in warmer climates

  5. gearsforguts
    Joined: Sep 18, 2005
    Posts: 413

    from temple,pa

    heat riser i believe,ive had early cast 2 barrel intakes that had them,ussualy on the 2 barrel intakes the carb studs would break off
  6. Fat Hack
    Joined: Nov 30, 2002
    Posts: 7,709

    Fat Hack
    from Detroit

    Thanks guys...

    I was thinking they had something to do with warming the stock carb up (since they go into the exhaust crossover), but did not know that the original carbs had cast iron bases on them!

    They'll be plugged for sure!!!
  7. Where'd you get that intake?:rolleyes: :D

  8. The carb area's very interesting looking, isn't it?
  9. I asked because he snaked it off my shelf at my "going away party". It's out of my 64 Impala SS, the stock intake for a 327 4 bbl. I think it had a Carter originally, but when I got it it had some bastard style Holley, and IDK if a "regular" (1850/60) Holley will fit or not.

  10. Musta been a good party......for him! haha
  11. willowbilly3
    Joined: Jun 18, 2004
    Posts: 4,356

    Member Emeritus
    from Sturgis

    Early Qjets had those too and you had to run the metal plate or cook the gasket pronto.
  12. David Chandler
    Joined: Jan 27, 2007
    Posts: 1,101

    David Chandler

    Yup, those are heat riser holes. Tap them out and screw a plug into them. They ran a sort of high tempreture gasket to insulate the carb base. Usually age makes them crack. I've tapped a couple of them for 1/2" bolts, then drilled and tapped a hole in from the outside and put in a set screw just to keep things from moving around. Just put a coat of high temp RTV on the bolt threads to take up any slop, lock the set screws and it's done. I've never had any issues with leaks after doing this.
  13. enjenjo
    Joined: Mar 2, 2001
    Posts: 2,533

    from swanton oh

    Mid 60s Chevy used a strange base on Holley carbs on some models, that covered those holes. A standard Holley will have a vacuum leak at that point, unless you use two gaskets and a seperator plate.
  14. Fat Hack
    Joined: Nov 30, 2002
    Posts: 7,709

    Fat Hack
    from Detroit

    Some clown boogied outta Michigan and left it behind!!:D :cool:

    Edelbrock used to sell a thin metal plate that they recommended for use on the original Performer intakes when running a square-bore carb instead of a spred-bore one (the manifolds would accept either). That plate (with two gaskets) would probably do the trick here like you mentioned, but in addition to that, I'd feel better blocking the holes as well.

    Thanks, All!!

    (You too, Jay!!;) :D )

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