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Opinion on Exhaust routing

Engines, Exhaust and Fuel Systems

  1. ImpJay

    ImpJay New Member

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    Hello fellow members!

    I´m asking about your opinions about how to route a dual exhaust system under a 79 Chrysler LeBaron. It`s a 4d sedan with a stock 360HD except no cat or Leanburn.
    I`m thinking about converting to duals with my dad, so which is the smartest way to get them to exit at the rear bumper?
     
  2. M_Body_Coupe

    M_Body_Coupe Well-Known Member

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    Must the 'rear bumper' be the target zone???
     
  3. Oldiron440

    Oldiron440 Well-Known Member

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    I like just behind the rear tires it saves a lot of grief.
     
  4. M_Body_Coupe

    M_Body_Coupe Well-Known Member

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    Same here...awesome solution if you are not limitting yourself to just the rear-bumper exit point.
     
  5. ImpJay

    ImpJay New Member

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    Thank you for both answers!
    To M_Body_Coupe: Yes, the rear bumper is the target zone, but we are still looking for other (possibly easier) options. That`s why it is only the preferred way to us to route the exhaust system.
     
  6. M_Body_Coupe

    M_Body_Coupe Well-Known Member

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    Here is what I ended up doing on my coupe (slightly shorter wheelbase than your 4dr - by about 4" I think, all of it in the rear seat floor area).

    pic7.jpg

    pic4.jpg

    pic8.jpg
     
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  7. Dr Lebaron

    Dr Lebaron Well-Known Member

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    Google-chrysler fifth avenue dual exhaust
    hqdefault.jpg hqdefaultgg.jpg
     
  8. Aspen500

    Aspen500 Well-Known Member

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    I know it's hard to see in the pics but, I ran both t-pipes out the right side of the car by crossing over above the axle. Despite how it looks, they don't touch anything. DSCF0002.JPG DSCF0004.JPG
    DSCF0005.JPG
    DSCF0006.JPG
     
  9. Duke5A

    Duke5A Well-Known Member

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    To get the pipes out the rear bumper on both sides is a lot of grief indeed - these guys are totally correct. You need to move the gas tank over a strap and elongate the filler tube. If that were it then it would be easy, but the way the tanks are on these cars the middle top where the vent is has a bulge and the trunk floor is pocketed to make it fit. If you attempt to move it over that bulge in the tank contacts the floor. Only option is to beat the shit out of it with a hammer to make room. If I had it to do again I wouldn't have done it this way...too late now. How Aspen500 and M_Body_Coupe did it are the options you want to go.
     
  10. jasperjacko

    jasperjacko Well-Known Member

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    I did 2.5" into Y and single 3" tail pipe. Simple and works great. Not as cool as 2 pipes, but works very well. 100_3759-jpg.jpg
     
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  11. Oldiron440

    Oldiron440 Well-Known Member

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    I bet it sounds good!
     
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  12. Grandmas84

    Grandmas84 Well-Known Member

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    Here's my 84. I used the A body Jegs dual exhaust kit. I moved my tank over one rib and extended my filler neck by 2" with a spare I had laying around. No problem with the tank not sitting right no hammering needed.
     
  13. BudW

    BudW Moderator Staff Member

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    The Late ’77 to early 79 (from 4/1/77 to 4/2/79) F & M-body uses a different tank than the late ‘79-89 FMJ-Body’s use and thereby has its own issues when the dual exhaust topic comes up.

    Of the three different FMJ fuel tanks used (’76-early ’77 – which has a large unmovable hump, late ’77 to early ’79, and late ’79 to ’89) – which last version is easier (if you want to call it easy) to move the tank over one grove with than the mid design is.

    I do agree that either of the above versions shown (above) are the better way to go.

    I’m thinking about going the route Aspen500 went – but having pipes stacked instead of side by side – possibly – for my preference is rear exit. I’m not to that point on my project – so this “tin can” is being kicked around, still.
    BudW
     
  14. Poly

    Poly Active Member

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    Our J has the routing described by Aspen 500 but it's just two stock 18 dollar tailpipes welded together. It was an afterthought because the Flowmaster 40s' dumped straight out forward of the axel. On acceleration the noise was too loud. You could hear the secondaries kick in.

    So this was to get the noise down and the heat scavenged elsewhere. The mufflers are too far rearward. So this would be critical in planning a new install.

    There is very little tolerance in placing the stacked pipes over the axel. Ours clunk occaisionally against the frame. And after removing the air shocks there is a rub against the passenger shock when encountering large heaves in the roadway. So that's what we've found with the stacked pipes. Possibly some points to consider.
     
  15. Poly

    Poly Active Member

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  16. Poly

    Poly Active Member

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    I like jasperjacko's install. Fully functional and much easier. I think that's what we will go with next time.
     
  17. 5th avenue Rob

    5th avenue Rob Active Member

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    Are the tailpipes only available for single exhaust?
     
  18. BudW

    BudW Moderator Staff Member

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    The only “over the counter” exhaust part(s) that is available (that I know of) for FMJ vehicles are:
    - Mufflers (various shapes, sizes, pipe sizes and manufactures)

    - The “Canadian” Y-pipe (when available) – which is the Y-pipe without the two pre-cats. Production of this part is intermittent, and I fear, might be close to end of production life. Walker 40430
    A Y-pipe with pre-cats (which I’m not sure why one wants this, unless required to due to emissions law). Bosal 0793002

    - (Rear) Catalytic Converter (two versions, one with A.I.R. tube from A.I.R. pump, and a version without the A.I.R. tube)
    Tube type Bosal 079009 or Eastern Catalytic 20120
    No-tube type Eastern Catalytic 70002 (with 1-7/8” inlet) or 20004 (with 2-1/4” inlet)

    - The Right tailpipe. Walker 45614 (1-7/8” diameter (48 mm).
    Note: there might be some other items (out of production or overruns) available on eBay or other sources, but the above parts are the only ones I know of on today’s part books for small blocks.
    I didn't look up anything on /6's.

    All the performance parts (factory dual exhaust, etc.) had dried up by the end of the ‘90’s.
    It has the appearance that even the rest of the exhaust parts might not be far from also disappearing from the part store shelves/warehouses.


    Some older muffler shops have books (not digital) that has data they can use to reproduce a pipe without seeing the car. Most muffler shops do not have these books/manuals.
    Any good muffler shop can make great fitting pipes without a stinkn' book.


    I have a brand-new tailpipe (Walker 45614, mentioned above) that I’m willing to give away if a person wants to pay freight (or pickup).
    I bought it and gave to a muffler shop to make a set of ’80 and up tailpipes at 2¼” diameter. They reversed the pattern to make the Left side. I made these pipes about a decade ago and they have are hanging in my garage rafters. I had these made before I found out about the fuel tank move and fuel filler neck issue - so not sure that I want to use them on my ’86 Fifth Ave – yet. Also, i've hadn’t gotten to the point I need to use them, just yet (the tailpipes are not for sale, at least until I make up my mind on it).
    I also had a small block 2¼” Y-pipe made up using an older smaller Y-pipe as a model – but I doubt I will use it either, so it is for sale.
    https://www.forfmjbodiesonly.com/classicmopar/threads/the-canadian-y-pipe.5866/ - the lower picture of first post is for sale (very cheap). The above-mentioned Walker 45614 tailpipe is free (plus freight) for anyone who wants it.


    For those interested, my ’77 Volare (318 2-bbl automatic), has 2-1/8” downpipes and 2-1/4 Y-pipe exit. The single cat converter (no A.I.R. tube) has a 2-1/4” inlet – but don’t remember the exit size (2-1/8” maybe?). As the exhaust cools down, it doesn’t take up as much space – so having an exhaust system that tapers down some helps to keep the exhaust drown noise down.

    The rear cat (with A.I.R. tube) inlet on my ’86 Fifth Ave (318 2-bbl automatic) is 1-7/8”.
    Bud
     
  19. 5th avenue Rob

    5th avenue Rob Active Member

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    Thanks for the info. I think I will go to the u pull it yard and take some mesurements. To poor to have it made. Maybe crown vic police pipes can be cut down