Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Intake manifold holes?

Discussion in 'The Garage' started by camok5, Jan 25, 2007.

  1. camok5

    camok5 1/2 ton status Premium Member

    Joined:
    Jun 25, 2003
    Posts:
    959
    Likes Received:
    13
    Location:
    Buellton, Ca
    Can some one tell me what the hole inside the manifold are for. I have seen them with and without these holes? You can see them when looking straight down through the carb opening, they are about 1/2'' wide. Kinda like these.

    [​IMG]
     
  2. sweetk30

    sweetk30 professional hooker Premium Member

    Joined:
    Nov 1, 2004
    Posts:
    25,526
    Likes Received:
    526
    Location:
    horseheads , ny 14845
    possible for heat riser flow or egr stuff. never seen a gm with them.
     
  3. 01maroonz71

    01maroonz71 1/2 ton status

    Joined:
    Jan 8, 2007
    Posts:
    1,553
    Likes Received:
    4
    Location:
    Palmetto, fl
    me either...the only thing i can think of is for is if under the manifold(between the block and manifold) there can be vaccuum nipples to run vac lines off of since i don't see really any up top.
     
  4. camok5

    camok5 1/2 ton status Premium Member

    Joined:
    Jun 25, 2003
    Posts:
    959
    Likes Received:
    13
    Location:
    Buellton, Ca
    There inside the manifold not under it (like in the pic) so I dont believe they would be vacuum ports. I pulled a GM edelbrock performer off the engine I'm building that had them. At first I though it was some kind of casting error but when I started looking online I found more pics of different manifolds with them. I'm still confussed as for what they are for and wouldnt fuel get trapped in there?
     
  5. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

    Joined:
    Nov 14, 2005
    Posts:
    23,029
    Likes Received:
    1,347
    Location:
    Kzoo, Mi
    being its a dual plane manifold; does the upper plane crossover the lower plane on that manifold?
     
  6. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,975
    Likes Received:
    189
    Location:
    Roy WA
    Oldsmobile used a setup like that, fed EGR through pipes screwed into the intake in about the spots in the picture.

    Never heard of it on Chev motors though.
     
  7. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

    Joined:
    Nov 14, 2005
    Posts:
    23,029
    Likes Received:
    1,347
    Location:
    Kzoo, Mi
    Are they threaded?
     
  8. camok5

    camok5 1/2 ton status Premium Member

    Joined:
    Jun 25, 2003
    Posts:
    959
    Likes Received:
    13
    Location:
    Buellton, Ca
    Nothing attaches to them they are just holes that go into the bottom of the intake(not threaded) and I have never delt with them before but the manifold came off a chevy engine( not the same as the one in the pic, just using it because it shows the holes clearly).
     
  9. camok5

    camok5 1/2 ton status Premium Member

    Joined:
    Jun 25, 2003
    Posts:
    959
    Likes Received:
    13
    Location:
    Buellton, Ca
    This is one like the one I pulled off.

    [​IMG]
     
  10. camok5

    camok5 1/2 ton status Premium Member

    Joined:
    Jun 25, 2003
    Posts:
    959
    Likes Received:
    13
    Location:
    Buellton, Ca
    Someone on Pirate just told me that they are the blow holes for the EGR, is this true?
     
  11. Russ

    Russ 1/2 ton status

    Joined:
    Feb 17, 2000
    Posts:
    509
    Likes Received:
    0
    Location:
    Summerdale AL
    The edelbrock TBI manifold I put on my big block has those holes also. They go to the EGR.

    Russ
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

    Joined:
    Dec 13, 2000
    Posts:
    26,975
    Likes Received:
    189
    Location:
    Roy WA
    Yeah, threaded.
     
  13. diesel4me

    diesel4me 1 ton status Premium Member

    Joined:
    Jul 24, 2003
    Posts:
    17,534
    Likes Received:
    920
    Location:
    Massachussetts
    probably EGR passages..

    Mopar small blocks used similar holes with "floor jets" inside the intake to allow EGR gases to mix in with the fuel/air mixture to be re-burned..I'd guess the Edelbrock manifolds use a similar setup,going by your photos...:crazy:
     

Share This Page