Exhaust Manifold Mod

Slant 6 Engines

  1. RustyRatRod

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

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    Don't know how many of yall are interested, but here's what I did. Well.......here's what my friend Freddie did. LOL Since I am a walking retard with a grinder, I asked my friend Freddie about enlarging a slant manifold outlet. He took it out to 2 1/4" with meat left over. He said he was sure it would go to 2 1/2" but we both agreed that it might be a little thin. At 2 1/4" it still has plenty left. He did a fantastic job going way into the outlet smoothing and enlarging the whole way. Here's the finished product along with an untouched original to compare to. I don't know what gains if any, but it can't hurt plus when I upgrade to the TTI slant six exhaust, it will be a better match.

    MANIFOLD COMPARISON.jpg ORIGINAL MANIFOLD.jpg MODIFIED MANIFOLD.jpg MODIFIED MANIFOLD1.jpg
     
    Last edited: Jun 15, 2020
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    • 340doc

      340doc Well-Known Member

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      Nice job! Cant hurt, right?!
       
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      • RustyRatRod

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

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        A couple more showing how far in he went with it. No, I don't think it can hurt at all. The plan is when I get the 225 built, I'll be pulling the 170 out of course and at that time I'll give the manifold back to Freddie so he can port match the manifold to the head, since the head for the 225 will be ported.

        VIXEN MODIFIED MANIFOLD2.jpg VIXEN MODIFIED MANIFOLD3.jpg
         
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        • R4Sedan

          R4Sedan Larry FABO Gold Member

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          I bet there will be a gain. Nice job
           
        • Perseus

          Perseus '65 Dart slantsix

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          Freddie did a good job. Thanks for showing the pics.
           
        • theFightingFew

          theFightingFew Always Learning/1975 Valiant Custom/1974 Valiant FABO Gold Member

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          oh man that is awesome... wish I woulda thought of that before bolting everything back on a few weeks ago... I'll have to file this under future projects. Thanks for sharing the info @RustyRatRod !
           
        • RustyRatRod

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

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          Maybe if I was able to afford to upgrade to the 32/36 Weber at the same time. As is, I don't know. As said, it caint hurt.
           
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          • toolmanmike

            toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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            Looks good Rusty! Smart guy to know your limits. If you have a buddy that can do a nice job let him do it.
             
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            • rumblefish360

              rumblefish360 So close, yet so far away FABO Gold Member

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              Holy Holland Tunnel that went big!
               
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              • toolmanmike

                toolmanmike FABO MODERATOR Staff Member FABO Gold Member

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                Rusty's /6 manifold

                tunnel-boring-machine-2-manu_bahuguna.jpg
                 
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                • ir3333

                  ir3333 Well-Known Member

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                  Great idea Rusty..hotrodding 1.0:1
                   
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                  • Treblig

                    Treblig Well-Known Member

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                    Freddie is infringing on my "patent"!!!!! LOL:poke:
                     
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                    • RustyRatRod

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

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                      That's what she said last night.
                       
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                      • MoparMike1974

                        MoparMike1974 FABO Gold Member FABO Gold Member

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                        That should make a huge difference mated up with some free flowing exhaust. Slants like to breathe. My first car was a 72 dart with a slant. I threw on some 2.25 pipe and a glass pack and it was like night and day.
                         
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                        • Mtrhead

                          Mtrhead Ace of Spades ♠️

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                          Old fashioned true old school hot rodding.....tip my hat to ya Rusty!!! Came out perfect..... been wanting to hog out of set of 273 manifolds ..
                           
                        • moparblood

                          moparblood Well-Known Member

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                          please update as to any gains, performance, etc..
                           
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                          • RustyRatRod

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

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                            ok, I'm updating. lol There is a definite change from about 2500 on up. No doubt. I think with the 2.5" exhaust, there will be even more added.
                             
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                            • briwill70

                              briwill70 Well-Known Member

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                              I did the same thing to mine when I rebuilt the engine. Runs good!
                               
                            • RammerJammer75

                              RammerJammer75 Well-Known Member

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                              What about the knock off Weber? I had one on a 2.6 Mitsubishi for years with no issues. Actually still have it.
                               
                            • briwill70

                              briwill70 Well-Known Member

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                              I accidentally ordered a Chinese weber and the quality was terrible. The butterflies rubbed on the throttle body and didn't open all the way. Sent back and got a real Weber.
                               
                            • RammerJammer75

                              RammerJammer75 Well-Known Member

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                              This has been probably 4 or 5 years ago and it didn't have any issues. Of course there's no quality control with those things, so maybe I just got lucky.
                               
                            • volaredon

                              volaredon Well-Known Member

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                              yup Ive done a couple of /6 exhaust manifolds the same way..... with another in the garage to "do it again" (think song by "Steely Dan")
                              I have never done anything to the ports on one, other than to clean up the hooks and sharp edges that would gouge my hands while handling.....
                               
                            • /sixchall

                              /sixchall Well-Known Member

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                              MoparMike1974, I do believe the Slant does like to breath. After I added the Super Six set-up on my ‘70 Dodge Slant6 I added a set of Hooker 3 into 1 headers into 2.25” real dual exhaust system with “H” pipe. Back to a pair of glass pack mufflers all the way to back of car capped with bright tips. Gives it a sound like a mild small block at Idle. Until you drive off then it does sound like a six.
                               
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