302 Heads in an Early A.

Mopar Exhaust Systems

  1. seabee

    seabee FABO Gold Member FABO Gold Member

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    From what I have read here (I think my eyes are bleeding at this point) the Early A 273 manifolds will not fit the 302 heads without some shaving off the head or manifold. I mocked them up and sure enough it is true.

    My original plan was to use the 273 manifolds and order the complete single exhaust from Accurate.

    Is there a later manifold, shorty header that comes out in the stock locations that would marry up to a Y Pipe? Or is TTI/Dougs dual exhaust the only way?
     
  2. Robbie2734

    Robbie2734 Lambcharger

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    Would the later (67-75) 318 exhaust manifolds work on that head without any interference? I would try them with the 318 Y pipe. I think Pypes also offered custom header pipes, you need to tell them the manifold casting numbers. Good luck.
     
  3. Treblig

    Treblig Well-Known Member

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    I have a set of pretty nice '69 318 heads with recent overhaul and only a couple of thousand miles on them. The '69 318 engine they came of off had 9.2:1 CR from the factory. I might consider selling them if they would work with your set up.

    Treblig
     
  4. seabee

    seabee FABO Gold Member FABO Gold Member

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    Thanks Treblig, I'll keep that in mind.
     
  5. seabee

    seabee FABO Gold Member FABO Gold Member

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    The main concern is the fitment around the steering shaft. The 273 manifold (#2465847)flattens out and goes around it like this:
    [​IMG]

    I think I might be able to use an exhaust flange like this:
    [​IMG]
    on the driver side to clear the bump on the head and still clear the shaft.
     
  6. Treblig

    Treblig Well-Known Member

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    The only small problem with using an exhaust spacer/flange is that it kicks the exhaust manifold further out toward the steering box and the steering shaft. But maybe you'll get lucky.

    Treblig
     
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    • seabee

      seabee FABO Gold Member FABO Gold Member

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      That's what I am worried about. I am going to mock them up tonight and compare the space between the fenders wall with pictures of the stock placement.
       
    • C130 Chief

      C130 Chief Mechanical Genius

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      Why not grind off the offending bit of head? I'm assuming you're having trouble with the drivers side manifold outlet pipe hitting the smog port boss under the #7 port.
       
    • pishta

      pishta I know I'm right....

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      :D:coffee2:
       
    • seabee

      seabee FABO Gold Member FABO Gold Member

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      Any water passage under there?
       
    • Treblig

      Treblig Well-Known Member

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      I switched to 302 castings on my 318 but the main reason I switched is that when I test fitted the 340 driver and 360 passenger exhaust manifolds there wasn't much sealing surface on the bottom of the port. So to make sure I didn't have any trouble using the 340 and the 360 manifolds I removed my original 318 heads and replaced them with the 302 castings. The 302 castings have a much larger (area) sealing surface below the exhaust port. But again, I own a '69 Barracuda which is about 1 3/4" wider between the inner fenders. The steering box and the steering shaft are also a little further away from the engine. Do you have a manual steering box??

      treblig
       
    • C130 Chief

      C130 Chief Mechanical Genius

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      I think you should be fine. Only about 1/4 inch needs to be removed, mostly from the edge of the pad. Those extended pads were added for AIR injection exhaust manifolds. I doubt the inner casting core was altered, to move the water passage outward. If anything the casting would have been made thicker to compensate for the thermal stress in the area.
       
    • seabee

      seabee FABO Gold Member FABO Gold Member

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      Thanks for the replies, you guys rock. I ground off the head. With a nice thick gasket (Remflex) should be fine.
      [​IMG]

      Also cut out the heater riser plate and will be tapping those holes tonight.
       
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