Intake manifold doesn't cover head properly

Discussion in 'Street/strip 400/430/455' started by Rui, Mar 4, 2018.

  1. Rui

    Rui Member

    Hi guys.

    The heads on my 455 block have open holes after installing the intake, refer pics.
    Is this normal, and if so how do I block up these holes?
     

    Attached Files:

  2. hugger

    hugger Well-Known Member

    You have the wrong valley pan gasket, you need a 67/71 what you have is the 72+ gasket
     
  3. flynbuick

    flynbuick Super Moderator Staff Member

    It appears that you are attempting to put a 70 stock intake on a set of post 71 emissions era heads without the correct modifications and gaskets.
     
  4. Electra Bob

    Electra Bob Well-Known Member

  5. buick64203

    buick64203 Just plum crazy Staff Member

    Yep, wrong intake and gaskets
     
  6. 436'd Skylark

    436'd Skylark Sweet Fancy Moses!!!!!

    the heads and intake are fine. the gasket is wrong. that upper hole is blind and are not covered.
     
  7. Rui

    Rui Member

    Thank you.
    I found the correct steel type valley pan gasket (see pic), with has an opening where the 2 round holes are.
    I also found another composite type gasket where these 2 holes are closed off.
    I live in a very warm climate country, which one should I get?
    And if I get the composite one with the 2 holes blocked off, do I need to worry about installing a tray baffle over the lifters?
    I'm worried the heat will over time pierce through the material.

    Appreciate the support.
    375-MS96005.jpg 375-1357.jpg
     
  8. john.schaefer77

    john.schaefer77 Well-Known Member

    You will need to modify the valley pan to be a baffle or buy the TA or American Machine and Performance pan if you are using the composite gasket. Cheapest way is to get the correct steel pan in my opinion.
    If you live in a warm climate the heat crossovers really aren' needed. I don' use them on mine and I live in Delaware but don't drive too much winter driving.
     
  9. No Lift

    No Lift Platinum Level Contributor

    The exhaust heat will blow through the composite FelPros in a few minutes unless the exhaust crossover holes are plugged off. Just use the sheetmetal gasket you have pictured in #7. I'd still install the correct diameter small freeze plugs to fit the 4 exhaust crossover holes. Just measure the diameter of the holes and get freeze plugs a tiny bit bigger and tap them in. They have to be a snug fit. I'm not sure of the exact size. That could add a few HP to the engine because the intake won't heat up as much especially since you live in a warm climate. Worst case if the choke doesn't pull off fast enough you pop the intake off and drill a 1/4" hole in one plug closest to the choke pulloff. For a mild build there is no reason to change from the stock style intake gasket.
     
  10. Rui

    Rui Member

    Perfect, thanks guys, I know what I need to do now.
     
  11. Rui

    Rui Member

    Just a quick update... correct valley pan gasket installed and crossover holes plugged.
    Thanks for all your help.

    IMG_7676.jpg IMG_7677.JPG
     
    john.schaefer77 and Harlockssx like this.
  12. tommieboy

    tommieboy Well-Known Member

    It's been such a long time since I worked on these engine.....

    Do these steel gaskets require something like a coating of permatex copper spray-a-gasket on both sides of the mating surfaces prior to assembly? My mind is drawing a total blank on this. Must be my age.

    Thanks,

    Tommy
     
  13. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD"

    Yes, gasket spray on both sides. RTV just around the water passages, both sides, and a dab of RTV at each end of the front and rear rubber seals where they tuck under the heads.
     
  14. tommieboy

    tommieboy Well-Known Member

    Thanks Larry!

    Tommy
     
  15. Grandpas67

    Grandpas67 Well-Known Member

    I used this info on my 350 intake install...worked like a charm. Glad I read this today because I'm about to do the same on the 455 we're building.
     

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