Exhaust for a 1973 Duster 340 (Pics Included)

Mopar Exhaust Systems

  1. Gold Crusader

    Gold Crusader Active Member

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    Hey guys!
    I am buying my very first muscle car! Been wanting one since I was 5 and now that I'm 26 I have the money! I'm so excited I can't stand it. Five more days... I just can't stop looking up youtube videos!

    It's a 340 wedge but I understand the wedge makes no difference but was just marketing? Or it does have some slight variation.

    Anyways, about the exhaust. The car comes with absolutely no exhaust and I have no real idea of what I'm doing. I'm in Texas so I am unaware of any laws that I need to be aware of. I know I don't need to worry about emissions but what about loudness? Are there any kits specifically made for the 73 Duster? Any tips or ideas of what I should get? I've never done this before and so this will be my first project. To get it street legal I just need the exhaust and a few bulbs.
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    00G0G_ivlAN9ijhzi_600x450.jpg 00S0S_hSfeO0wY63Y_600x450.jpg 00N0N_1M2UwUWbU2Q_600x450.jpg
     
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    • dogbreath

      dogbreath Well-Known Member

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      summit hooker headers $210 summit exhaust $260
       
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      • diymirage

        diymirage HP@idle > hondaHP@redline

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        It does have manifolds...that is "some" exhaust
        That alone with some downpipes and the kit puppy mentioned are fine

        After that, it becomes a checkbook decision
         
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        • sireland67

          sireland67 Well-Known Member

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          Since you have manifolds, a trip to a local exhaust shop, and have them bend you up a set of duels.
           
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          • canyncarvr

            canyncarvr Well-Known Member

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            In answer to the first question:

            Curious: What makes you think it's a 340?

            I'm not an expert on the matter...or even a slow drip under no pressure at all...but the lack of a vacuum boost on the brakes is one thing that makes me wonder.
             
            Last edited: Apr 15, 2019
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            • MoparMike1974

              MoparMike1974 Well-Known Member

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              All 340's were wedge, its a marketing ploy. That decal is not correct for 73 anyways, someone liked it so they put it on the car.
               
            • sireland67

              sireland67 Well-Known Member

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              I have seen more 340 cars without power brakes, than with them.
               
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              • MoparMike1974

                MoparMike1974 Well-Known Member

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                Yes, seems that was the norm. I guess money was tight after the engine upgrade so they settled for manual brakes. Not many 340 cars had AC either.
                 
              • RustyRatRod

                RustyRatRod 30 Degrees Outta Whack FABO Gold Member

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                You can do headers if you want, but if the engine is stock or close to it, I would just come off the manifolds with a good dual exhaust system with something like Dynomax Ultraflow mufflers with tail pipes in the stock location.
                 
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                • canyncarvr

                  canyncarvr Well-Known Member

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                  '73 Dusters?
                   
                • Gold Crusader

                  Gold Crusader Active Member

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                  Ya I heard a lot of people like the Dynomax Ultraflows. So, would I just need to buy the mufflers and have the shop do the rest?
                   
                • Ccas

                  Ccas FABO Vendor FABO Vendor

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                  Texas laws and federal laws are quite different. Federal law says you may not 'delete' the catalytic converter(s). State laws in texas even vary by county. There may not even be a visual inspection required depending on your county.

                  Sound ordinances are usually town or township based and are rarely enforced. You really have to look or act obnoxious to get a ticket for loud exhaust in most towns. So the sound you choose be can and should be what you like.

                  As far as what exhaust you pick, you can spend very little or you can spend a lot. The better exhaust kits will be mandrel bent piping and allow your engine to breath better and free up anywhere from 10-50 hp. It all depends on how much hp the motor is to start with. The muffler you choose has much less affect on the performance than the pipes do. Local shops and cheap online sources use compression bent piping that flow poorly. Again, it's all about your situation, your budget, your driving habits etc.

                  I'd like you to take a look at this exhaust system as an option for your Duster.

                  67-73 Mopar A-Body 2.5" Crossmember Back w/ X-Pipe System SMA10

                  If you are interested, PM me for a special member price.

                  Good luck with your new Duster!
                   
                • Jadaharabi

                  Jadaharabi FABO Gold Member FABO Gold Member

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                  73 did not have catalytic converters.
                  Texas law used to be that the exhaust has to exit the body. In other words you cannot dump the exhaust in front of the rear axle and be legal. That's why you see a lot of side pipes in Texas.
                   
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                  • tonysrt

                    tonysrt FABO Gold Member FABO Gold Member

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                    Pypes only makes from headers back and not to exhaust manifolds. They were at Englishtown and I asked and that was their response. If you have head pipes off manifolds maybe you could adapt them.
                     
                  • Ccas

                    Ccas FABO Vendor FABO Vendor

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                    Good point. I should have mentioned that but someone mentioned headers so I was kind of picturing an upgrade to headers which would be a good option. Pypes is also interested in making a nice pair of 340 manifold downpipes for the duster if someone wants to let us borrow their Duster for a bit. :)
                     
                  • moparmandan

                    moparmandan FABO Gold Member FABO Gold Member

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                    There are a lot of options for exhaust. Some expensive, some not so bad. This depends if you can do it yourself and you have a shop to work out of, and can use something prefabricated that bolts or welds together. If you're like most 26 year old guys with their first muscle car, budget is an issue. Drag it down to the local muffler shop. They should be able to get you fixed up from the manifolds back, affordably.
                     
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                    • moparmandan

                      moparmandan FABO Gold Member FABO Gold Member

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                      Why you hating on Darts and Scamps? :poke:
                       
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                      • moparmandan

                        moparmandan FABO Gold Member FABO Gold Member

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                        They're great mufflers and sound amazing. But there's nothing wrong with the muffler shop stock $20 turbos either. They certainly won't last as long as a good stainless muffler. Just to get you going.
                         
                      • Gold Crusader

                        Gold Crusader Active Member

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                        Thank you so much! I do have it in my budget to get a nice set of mufflers :) However, I'm sorry but I'm still a little confused. I take it to the shop with just the mufflers and just have them add the pipe? Will it be just straight pipe or an x pipe or an H pipe? I'm the epidomy of a noob here lol I really appreciate all this help
                         
                      • rumblefish360

                        rumblefish360 so close yet so far away

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                        If it is anything near a good shop they will just take the mufflers and make the rest up for you. They have to be able to bend the pipe themselves.

                        Are you staying with exhaust manifolds?

                        Oh! Welcome to the MoPar club and its madness!
                         
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                        • Gold Crusader

                          Gold Crusader Active Member

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                          Thank you! Everyone has been so helpful! Also, I’ve done som research and apparently headers wouldn’t have as much compression freeing up for hp? If that’s the case then I’d like to invest in headers.
                           
                        • rumblefish360

                          rumblefish360 so close yet so far away

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                          Compression? That word is associated with the engines “compression ratio.” Perhaps you mean the exhausts “back pressure?”
                          Headers as well as the rest of the exhaust help reduce if not eliminate back pressure. Anybody, and I really mean anybody, tells you that you need exhaust back pressure, just smile and walk away, quickly, actually, run your ass off like there is a pending bomb in your ass checks.

                          A member above made an excellent suggestion with Hooker or Summit headers and there exhaust kit. I suggest the exhaust kit at 2-1/2 inches and! Purchase there “H” pipe kit to splice in. A chop saw or any circular power saw with a metal blade for quick, clean and straight cuts is advisable. A chop saw works best.

                          This do it yourself “kit” is EZ to do and a beginner can do it. If it is your first time, it may take two days. When your old and wrinkly riddled with arthritis and bulging disks like me, it takes half a day. I’ve done it a lot for myself and friends.

                          Measure twice, cut once!
                          A sharpie helps A LOT!
                           
                        • rumblefish360

                          rumblefish360 so close yet so far away

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                          Page 4 of this old thread shows some of the Hooker headers + Jets exhaust (same as Summit’s exhaust kit) minor trimming needed.

                          rumblefish's Duster project

                          The summit exhaust kit comes with mufflers, Jets has the option without mufflers.
                           
                        • Ccas

                          Ccas FABO Vendor FABO Vendor

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                          Since they are A-bodies as well, I'd be fairly confident we could design a 340 downpipe kit that would fit both the Dart/Scamp/Duster and Demon's.
                           
                        • canyncarvr

                          canyncarvr Well-Known Member

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                          ....I still want to know why it's 'known' to be a 340..... 'Lots of 340s had manual brakes...' didn't answer the question as to the '73 part of the equation.

                          Not that a 318 can't be fun. If someone is expecting 'x' amount of performance from an engine, it helps to know what they're starting with.

                          OK. I'll ask. What's the VIN number? Does it match the title VIN?

                          The VIN doesn't say it's a 340 or not, but puts a direction-of-lean on the sitchiatiown.

                          No one with any comment on the stripes? As in.....they aren't Mopar stripes is my bet. Not that this makes it gospel, but I've never seen anything like 'em.

                          Not trying to rain on anyone's parade. Just looking for the facts of the matter. The OP is likely paying a lot more money it being a 340 than if it was the 340's little brother.
                           
                          Last edited: Apr 17, 2019
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