Exhaust Pipe Diameter 273

Mopar Exhaust Systems

  1. MoparDart68

    MoparDart68 Well-Known Member

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    Just wondering what size exhaust piping I should be running behind a stock 273 2bbl. Been wanting to do a dual exhaust system for a while from the manifolds back. Thoughts on H or X pipe? Is it even necessary with a stock motor like mine? Undecided on mufflers too, any suggestions would be appreciated. Thanks!
     
  2. Abodybomber

    Abodybomber Breaking street machines , since 1983.....:) Legendary Member

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    2 1/4"- 2 1/2".,be good. Spend the extra money ,on over the axle tailpipes. Your ears,will thank you.
     
  3. /6 Matt

    /6 Matt 30 Degrees Crooked

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    If its stock I would say 2-1/4" dual and use the X-pipe. X-pipes always give gain. Are you running headers or manifolds?
     
  4. lou3500

    lou3500 Fla. Cuda Guy

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    I have a 66 cuda with a 273 2 bbl motor [running a 4bbl intake] stock manifolds I have a true dual 2 1/4 system [no x or h pipe] 1 7/8 head pipes [to the bottom of firewall] stepped up to 2 1/4 stepped up to 2 1/2 at the mufflers and tips. I'm running Magna flow Magna packs [stainless straight thru] mufflers with stainless oval tips. Sounds awesome [quite loud] inside and out. My exhaust guy asked what I was wanting and I said I wanted to make small children cry when it was running he gave me what I wanted.
     

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  5. TrailBeast

    TrailBeast AKA Mopars4us on Youtube

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    Everything I have ever seen says the smaller the cubic inches, the more difference the X pipe makes.
     
  6. roccodart440

    roccodart440 Well-Known Member

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    Whatever size your collectors are is ideal however that isn't always possible.

    X pipe over H pipe but it isn't necessary but will yield you multiple gains over a straight dual system.

    Mufflers...anything but flowmasters will be fine.
     
  7. 340 8BBL

    340 8BBL Well-Known Member

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    if its bone stock,and you plan on keeping it stock or close to it,id run dual 2" front to back.an x or h pipe will smooth up/quiet the exhaust note some and possibly add a little low end over true duals.as for mufflers.....any decent performance muffler will do its more about the sound you want.
     
  8. 1968FormulaS340

    1968FormulaS340 Well-Known Member

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    Minimum I would put on any V8 is 2 1/4". This will be fine on a stock engine and give you wiggle room for adding more power later.

    2 1/4" will support your average street machine, running 13s, all day long.

    If your future plans include getting more serious, pushing into the low 12s, high 11s for example, don't buy twice, just get 2 1/2" now.
     
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    • MoparDart68

      MoparDart68 Well-Known Member

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      Thanks for the input everyone! I'm running the stock manifolds btw. I got an estimate a while back: $650 [FM 40 series, without an X-Pipe (seemed a bit high)]. Thinking I might shop around a bit more...I know a lot of people are anti-flowmaster. I've always loved the sound, but not so sure it would sound right on a 4-Door.

      Making small children cry?? That's a new one, lol.
       
    • MoparDart68

      MoparDart68 Well-Known Member

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      Never plan to go that far. When I eventually rebuild the 273, I might hop it up a bit to commando specs, but that's about it. I like the idea of having a smaller displacement and original block in the car. Would 2.5" be overkill for now on the stock motor?
       
    • 1968FormulaS340

      1968FormulaS340 Well-Known Member

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      If it were my car, given your performance goals, I would go with 2 1/4". I wouldn't even think about using 2 1/2".

      I would also go with DynoMax Super turbos. I can't stand Flowmasters, but this is personal preference.
       
    • 340 8BBL

      340 8BBL Well-Known Member

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      well being a fabricator by trade,and having built multiple exhaust systems,id say 2.5 duals it a little overkill for a stock 273.considering the opening on the exhaust manifold is like 1 3/4"-1 7/8" it would be like hooking a fire hose to a residential hose bib.plus its heavier,harder to route,and more expensive.if you look at the commando 273 exhaust its a very well thought out system.the y pipe dumps into a single 2.5 mid pipe with a 2.25 tail pipe.the pics posted of the 2.25 system with magnapacs is also a good example of a well crafted system,but its the largest id go for what you are doing.jmo.
       
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      • lou3500

        lou3500 Fla. Cuda Guy

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        Thanks 340 I went to an exhaust guy that I was referred to and he fabricated what you see for about 5 bills, it sounds awesome no rattles and everything is even [the guy is a perfectionist] he recommended no x or h pipe he bumped it to 2 1/2 for the muffs and tips for more sound, I am going to do some head work and port match everything when I rebuild the motor. I like loud my motto if you can't hear it, it ain't worth havin!!!
         
      • MoparDart68

        MoparDart68 Well-Known Member

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        Thanks for the pics, Lou. Nice setup you have there.
         
      • rumblefish360

        rumblefish360 I have escaped the evil Empire State! FABO Gold Member

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        Flow Masters just do not flow so well. That's why most are anti Flowmaster.
         
      • RedFish

        RedFish Well-Known Member

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        With 40 series flow masters, don't plan on listening to the radio or anything other than exhaust drone. The single left to right strap under pre 68 fuel tank will likely be in the way. There are routes around it but I thought I should mention it just so you know what's in store.
        A good bit of restriction exists in those stock manifolds so dual pipes wont have much effect on performance.
         
      • MoparDart68

        MoparDart68 Well-Known Member

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        I had the 40 series on my 318 Duster. Paired with headers, they were pretty loud at the tips. I decided to chop off the tail pipes (just behind the muffler outlet) one day to see what kind of racket I could make. Now, that was some serious noise right there, especially inside. They sounded great once you got on the throttle, but I couldn't hear my sound system anymore...Not really going for performance, just sound.
         
      • roccodart440

        roccodart440 Well-Known Member

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        Those are my 2 issues with flowmaster. They don't "flow" and the interior resonance and or noise is too much. I've run glasspacks that were quieter inside the car.
         
      • dynodonn

        dynodonn Well-Known Member

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        My 1965 Barracuda has the 235 HP Commando engine, and I'm running stock exhaust manifolds with 2-1/4" pipes, no "X" or "H" pipes, & Flowmaster SS mufflers. It sounds great.
         
      • lou3500

        lou3500 Fla. Cuda Guy

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        This was requested sound clip of my magna flow magna packs in my garage.

        [ame="http://s1138.photobucket.com/user/lou3500/media/cudaexhaustsound_zpscbf913da.mp4.html"]Cuda Exhaust Sound Video by lou3500 | Photobucket@@AMEPARAM@@http://i1138.photobucket.com/albums/n522/lou3500/bth_cudaexhaustsound_zpscbf913da.mp4@@AMEPARAM@@1138.photobucket.com/albums/n522/lou3500/bth_cudaexhaustsound_zpscbf913da.mp4[/ame]
         
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