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    Author Topic: Help , Im getting lost!  (Read 1708 times)

    Offline Dev1Motorsports

    • Jr. Member
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    • Posts: 6
    Help , Im getting lost!
    « on: May 25, 2016 - 07:11:10 PM »
     :feedback:

    So I took my Stock 72 Challenger Rallye to my local hotrod shop to gt an exhaust leak fixed.  The milled the manifolds due to leaking from the center ports.

    He went to re-install and they still leak from the same spot.  The man has been doing exhaust work on muscle cars for years. so im not dealing with unexpirenced tech

    any ideas
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    1967 Dodge Polara 440 HP(1969)
    2008 Dodge Caliber SRT4 (sold)
    1972 Challenger Rallye keeping original


    Offline 1 Wild R/T

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    • Posts: 4594
    Re: Help , Im getting lost!
    « Reply #1 on: May 25, 2016 - 07:19:05 PM »
    Yeah, check to see if there are small holes below the manifold, Starting around 73 Mopars started using Air Injection, the heads have small ports where air was injected, if you bolt early manifolds on late heads those ports are exposed & the result is an exhaust leak....  Tap the holes to 1/4-20 & screw in set screws....
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    JS27N0B 70 Challenger R/T Convertible  FJ5 Sublime, Show Poodle w/90,000 miles since resto
    WS27L8G 68 Coronet R/T Convertible  PP1 Bright Red, Project
    RM21H9E 69 Road Runner Coupe R4 Performance Red, Sold...
    5H21C  65 Falcon 2 dr Wagon... Dog Hauler...

    Offline Dev1Motorsports

    • Jr. Member
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    • Posts: 6
    Re: Help , Im getting lost!
    « Reply #2 on: May 25, 2016 - 07:54:53 PM »
    Thank You.  I have now confirmed that it is a 1972.  We will double check to make sure that they are not  73's.
    Again Thanks for the quick reply
    Logged
    1967 Dodge Polara 440 HP(1969)
    2008 Dodge Caliber SRT4 (sold)
    1972 Challenger Rallye keeping original

    Offline Dev1Motorsports

    • Jr. Member
    • **
    • Posts: 6
    Re: Help , Im getting lost!
    « Reply #3 on: May 25, 2016 - 08:10:47 PM »
    So Just got a call from the Shop. Comes to find out that the manifold gaskets WITHOUT the  smog air injection holes are too small. Have to use the ones with the smog air hole they will correctly fit the 72 J heads. Thank you 1 wild R/T . for the recommendation it was a point in the right direction.
    Logged
    1967 Dodge Polara 440 HP(1969)
    2008 Dodge Caliber SRT4 (sold)
    1972 Challenger Rallye keeping original

    Offline YellowThumper

    • Sr. Member
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    • Posts: 1633
    • I left the snow for this?
    Re: Help , Im getting lost!
    « Reply #4 on: May 26, 2016 - 02:07:33 PM »
    Glad you got it sorted...

    Fwiw The 318 manifold flanges and gasket openings are much smaller in size also.
    Mixing and matching of wrong but similar looking pieces will leak.
    360/340 manifold openings are larger than the machined flanges on a 318 head.
    Ask me how I know this...
    « Last Edit: May 26, 2016 - 02:52:57 PM by YellowThumper »
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    Removing the warning labels one at a time.
    Nature will take care of the rest.

    Offline burdar

    • Sr. Resident
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    • Posts: 5925
    Re: Help , Im getting lost!
    « Reply #5 on: May 26, 2016 - 02:47:17 PM »
    You shouldn't need any gaskets at all.  The factory didn't use any gasket on the exhaust manifolds since they are a machined surface.  I used a little copper RTV on mine when I put it back together since I didn't have them resurfaced.  No leaks there.  My heat riser shaft is leaking a little bit though.  Make sure that's not where the leak is coming from.  Use a stethoscope to determine exactly where the leak is.

    I didn't think the air injection holes showed up until the 80's.  My 73 318 didn't have them and my 76 360 didn't have them either.
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