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Thread size/pitch on intake manifold

Discussion in '40- & 55-Series Tech' started by CruisinGA, Jan 5, 2004.

  1. CruisinGA

    CruisinGA

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    Anyone know the size of the thread/pitch of the vacuum fitting that screws into the manifold just in front of the carb. The one with two small vac lines coming out. It seems to be the same as the diff. breather, which is close enough to 1/8th" NPT for practical purposes.

    #2 The intake manifold is aluminum, correct? If so, is it like steel in that it is harder than brass so brass fittings will give way, or is it soft enough where I had better not try?

    #3 If I cannot use brass NPT fittings in the intake manifold, is there a safe was to get a single fitting for 1/4" ID hose using that tapped hole in the intake manifold? (without drilling out to accept 1/4" NPT)

    Thanks.
     
  2. IDave

    IDave

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    Picture please? I don't think I have a vacuum fitting where you're talking about, Bailey. The manifold is aluminum, and there is a brass screw plug that goes into the hole where the brake booster plugs in, if you don't have a booster. Does that info help at all?
     
  3. 73lndcrsr

    73lndcrsr SILVER Star

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    I don't know the exact pitch, but you should be able to use a brass fitting. Just be careful when you tighten it down. I have used common brass fittings in other ports on the manifold without too much difficulty.
     
  4. CruisinGA

    CruisinGA

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    Alright.
    The vacuum fitting supplied vaccum to my VSV and other long gone vacuum equipment. I no longer need a vsv, I only need one large vacuum line to run to the new big cap dist. and charcoal canister.
    I may end up using brass, good to know it will work.
    Pic tomorrow.

    One option may be to use the breather fitting off of a 60 series axle, should be correct thread, and is the right hose size, AND is a 90 degree elbow which is better.
    Problem is finding someone willing to part with one.