High flow exhaust Manifolds?

Mopar Exhaust Systems

  1. swingingdart

    swingingdart Well-Known Member

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    Does anybody make high flow exhaust manifolds for a bodies? I have headers, but am getting tired of the clearance issues I am having with them. I've smacked high spots in the road twice now and one pipe is almost collapsed. I'd love to go back to manifolds, but not the crappy flow!
    Any help is appreciated! Thanks!
     
  2. RustyRatRod

    RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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    Chrysler did. Big block? Small block? Slant six? Briggs and Stratton? It helps if we know what you have.
     
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    • toolmanmike

      toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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      67-69 340 manifolds are the best flowing. You can find them here through a wanted thread. You didn't mention what year or model but it doesn't matter much. Most manifolds fit most applications.
       
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      • swingingdart

        swingingdart Well-Known Member

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        I just thought about this!
        SORRY FOLKS! 1972 Small block, LA 318.
         
      • H22A4

        H22A4 Well-Known Member

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        You can’t have your cake and eat it too. Headers = high flow but clearance issues. Manifolds = less flow but no clearance issues.

        Which do you prefer? High flow or no clearance issues?

        It’s impossible to have manifolds without crappy flow (relative to headers) so don’t even state that.
         
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        • pishta

          pishta I know I'm right....

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          Ask @Treblig if Magnums will fit, and look for the early 92-93 big mouth '617-8' castings.
          53006617(driver's side)
          53006618(passenger's side)
           
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          • 4mulas

            4mulas Fixem'up

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            yes the late 67-70/early 71 manifolds, then they changed in mid 71 to-74 ish which are still good, just not known as being as good as the earlier ones. I may have a passenger side one I might part with.

            tti headers are known for better fitment too.
             
            Last edited: Jul 24, 2020
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            • pishta

              pishta I know I'm right....

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              If it were only available again.....
              1309-mopar-max-wedge.jpg
               
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              • RustyRatRod

                RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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                I would talk to @Treblig first and see what he says. I tagged him so he'll come sniffin around. lol
                 
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                • RustyRatRod

                  RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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                • Tad

                  Tad New paint! FABO Gold Member

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                  5.9 magnum exhaust manifolds work with a little work!
                   
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                  • hemisedan

                    hemisedan FABO Gold Member FABO Gold Member

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                    I can’t remember what the company’s name is, but there is a company in the Northwest, Seattle I think, that is making the 68-71 high performance 340 manifolds now. They are an exact copy of those. I, almost went with them, but was able to find a good stock set. Blast them, weld on ear on one of them, and finish coating them. Look as good as new.

                    114F37EC-13DC-42D4-85A8-90506AAD3205.jpeg

                    BBEDB23E-6AFA-4030-A234-CC7D3EDD5AFF.jpeg
                     
                  • moparmat2000

                    moparmat2000 FABO Gold Member FABO Gold Member

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                    Yep 68-71 340 hi po manifolds. From what I understand these flow about as good as shortie headers. They are pricey nowadays and originals are in limited supply. As hemisedan stated theres repops of them out there if casting numbers and originality dont interest you. I dont believe the repops come with a heat riser flap or the holes drilled for one. The bosses are cast in for a heat riser however.
                     
                    Last edited: Jul 24, 2020
                  • swingingdart

                    swingingdart Well-Known Member

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                    Yeah, I dont really care if they are original. It's a 318 so it wouldnt be original anyway! Okay, from what everybody has said I'll be on the look out for some hi po exhaust manifolds, I appreciate everybody's help! It's awesome being part of fabo where everyone is willing to lend some advice!
                     
                  • 66fs

                    66fs FABO Gold Member FABO Gold Member

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                  • 66fs

                    66fs FABO Gold Member FABO Gold Member

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                    Original 318 manifolds will work just fine. Delete the flapper valve, ceramic coat them inside and outside, be done forever.

                    Header/manifold dyno test
                     
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                    • moparmat2000

                      moparmat2000 FABO Gold Member FABO Gold Member

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                      If your running a performer RPM you wont have a heat riser in the manifold and wont need the heat riser flapper.
                       
                    • YY1

                      YY1 Well-Known Member

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                      Are 360 manifolds bigger than 318?

                      Either HP or not...
                       
                    • toolmanmike

                      toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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                      yes 273/318 are the small port and 340/360 are large (larger)
                       
                    • pishta

                      pishta I know I'm right....

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                      IIRC Year One has the 340 clones @ $750, AAR clones and casting numbers but fit and function as A as well. For $750, you can get originals with the heat riser and have $300 to spare, just search around.
                       
                      Last edited: Jul 24, 2020
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                      • swingingdart

                        swingingdart Well-Known Member

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                        I'm running 302 heads, do those have any bigger exhaust ports?
                         
                      • toolmanmike

                        toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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                        no
                         
                      • pishta

                        pishta I know I'm right....

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                        wonder how bad these flowed? Marine app...probably didnt 'flow' at all, but just dumped

                        exhaust-cm-318-360-end-cat.jpg
                         
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                        • RustyRatRod

                          RustyRatRod Bla de blizhibliz de blatde blizi bla bla FABO Gold Member

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                          I know that's true of the intake manifolds (mostly) but are you sure about that on the exhaust manifolds? That's one I've never heard. Not that means a damn thing. lol
                           
                        • toolmanmike

                          toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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