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Pypes 2.5 in. Stainless Steel Replacement Flow Tube Kit (79-04 All, Excluding 03-04 Cobra)

Item 20109
Market Price $85.99 You Save 13% ($11.31)
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    Features, Video & Details

    • Required for Aftermarket Muffler Installs
    • Mandrel-Bent Construction
    • 2.5" 409 Stainless Steel Tubing
    • Fits 1979 to 2004 Mustangs

    Review & Installation Video

    Review & Install Video

    The Pypes 2.5-inch stainless steel replacement flow tube kit fits '79 to '04 V8 and V6 Mustangs, and '94 to '99 Cobras. You're gonna wanna check out a kit like this if you're upgrading your exhaust in stages by buying a mid-pipe and then buying a set of mufflers, in whatever order, instead of picking up a cat-back. A cat-back comes with these flow tubes, which are located between the mid-pipe and the mufflers, but if you pick up just a set of mufflers instead of a cat-back, you're looking at needing to reuse your stock flow tubes or picking up these Pypes flow tubes if you wanted to create a full aftermarket system from the mid-pipe back. The install for these isn't difficult. It's a one-out-of-three wrenches on the difficulty meter, and you can plan on spending an hour or two on the install. Sitting between the mid-pipe and the mufflers are the flow tubes. Unless you pick up a cat-back, you aren't getting a new set of these. They don't come with new aftermarket mufflers or mid-pipes, and a lot of people want to be consistent with their exhaust. That means not reusing the stock flow tubes. These flow tubes are 2.5-inch, mandrel-bent, 409 stainless steel. And I'll always say this when it comes to exhaust, but stainless steel's going to be your best bet if you want materials that are gonna hold up and not corrode. Compared to aluminized tubing, any stainless steel's gonna be stronger with a longer life. If you compare 409 to 304 grade stainless, 304's gonna be the top-of-the-line material. 409 stainless is still stainless steel, and it isn't a bad material by any means. You still get the longer life and the protection, but 409 usually costs a little bit less than 304. Speaking of cost, you can expect to pay right about $60 for these. These are currently the only flow tubes that you can pick up on the site, so there isn't really anything that we compare them to, but you know that they're 2.5-inch, and they're stainless steel, and they will fit with any setup. When it comes to the install, this is gonna be a one-out-of-three wrenches on the difficulty meter. You can plan on spending an hour or two, tops, on the install. You'll need a socket set and a way to get the car in the air. Depending on what else you're installing with these, the install might change slightly. If you're just installing the flow tubes and nothing else, the install will be straightforward. Your mufflers should have four clamps on them. You'll remove the two front clamps after unbolting the front flow tubes from the mid-pipe. Remove the flow tubes and swap in your new ones. Clamp them to the muffler, and then to the mid-pipe. I would leave things loose until you have them all lined up, and then tighten them down. And that's gonna wrap things up for the Pypes stainless steel replacement flow tube kit for '79 to '04 V8s and V6s, and '94 to '99 Cobras. You can check them out more online, right here at

    Replacement Flow Tubes. Replacing the restrictive stock mufflers is a great idea, but you may end up damaging the factory flow tubes in the process. That is why we offer Pypes 2.5" Stainless Steel Replacement Flow Tube Kit. This kit will replace the piping between the Mid Pipe and the mufflers for a perfect installation.

    Durable Stainless Steel Construction. Pypes uses sturdy 16 gauge 409 stainless steel mandrel bent 2.5" tubing with a ball and socket-style connector for improved flow and includes a set of two 2.5" 304 stainless steel flanges.

    Application. This Pypes 2.5" Replacement Flow Tube Kit is designed for use on the 1979 to 2004 Mustangs when replacing the stock mufflers with aftermarket mufflers or resonators.

    Fitment: 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 Details

    MPN# PFF10K

    CA Residents: WARNING: Cancer and Reproductive Harm -

    What's in the Box
    • (2) Flow Tubes
    • (2) Brackets
    Installation Info
    Tech Specs
    Will it fit my Mustang?
    • Bullitt - 01
    • Cobra - 93, 94, 95, 96, 97, 98, 99, 00, 01
    • Cobra R - 93, 95, 00
    • GT - 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04
    • LX - 87, 88, 89, 90, 91, 92, 93
    • Mach 1 - 03, 04
    • Other - 79, 80, 81, 82, 83, 84, 85, 86
    • V6 - 94, 95, 96, 97, 98, 99, 00, 01, 02, 03, 04

      Customer Photos (11) Submit Your Photo

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        Questions & Answers (12)

        5 Top Rated Questions

        Will these fit in place of the mufflers if they are cut out with a stock H-pipe?

        • This kit will replace the piping between the mid pipe and the mufflers

        Helpful (0)

        Does this just make it look cleaner after doing a muffler swap? Does it do anything else?

        • The Pypes 2.5 in. Stainless Steel Replacement Flow Tube Kit is designed to replace rotted flow tubes, or to use in custom exhaust setups.

        Helpful (0)

        I need to know what the bolt hole spread is ? On my headers the spread is 3 1/2 inches . It is 2 1/2 pipe . Is the flow tube , from the header back ? Is the flange spread the same?

        • From center to center of this flange will be approximately 4-1/4".

        Helpful (0)

        I need to know what the bolt hole spread is ? On my headers the spread is 3 1/2 inches . It is 2 1/2 pipe . Is the flow tube , from the header back ?

        • The Pypes 2.5 in. Stainless Steel Replacement Flow Tube Kit are designed to connect to a standard Mustang H pipe or X Pipe flange, and will not work with most headers. These pipes go from the mid pipe to the muffler.

        Helpful (0)

        Do I have to buy these if I'm buying an x pipe and flowmaster mufflers

        • Hey Vincent, You do not HAVE to buy them, they just clean up the piping of the exhaust system by replacing your stock pieces. but your x pipe and flowmasters should bolt on regardless

        Helpful (0)
        Post Your Question
        7 More Questions
        Do these bolt on directly to the bracket after the cats? 1 answer
        Will the m- 80 pypes mufflers slip into each end of the flow tube? That way I could just clamp them or will they not fit into each other and require welding? 1 answer
        Where can I find the bolts that go along with this piece? 1 answer
        can you use these to replace where the catalytic covers were welded on? or can i use any kind of straight pipe for that? 1 answer
        x pipe h pipe do these replacement pipes fit for both x pipes and h pipes or r they specific to a set up? 1 answer
        Lenght What is the length of these pipes? i want to make sure they will bridge the gap from my h pipe to mufflers 1 answer
        3 inch mufflers Are these ok to flair to accept 3" flowmaster 10 series 1 answer

          Customer Reviews (79) Write a Review

          Overall Rating 4.6

          out of 5 stars

          • 5/5

            September 23, 2019

            Perfect Fit

            These are a must if replacing your mufflers. Great quality and more importantly the right length. I installed with Flowmaster Super 44’s and worked out great.


            Year: 2001 Submodel: GT

            Helpful (0)

          • 5/5

            June 17, 2019

            Go with the FLOW!

            Great quality flow tubes with a great discount price. Can’t wait to install these with my SVE X-pipe, BBK headers, flow master mufflers and new flow master tail pipes. Now my new exhaust build is complete for my drop top pony. Thanks American Muscle.


            Year: 1991 Submodel: GT

            Helpful (0)

          • 5/5

            April 05, 2019


            Perfect fit, a cat back system isn't really available for a 84, so had to get part from different spots to make one. These pipes were cut and bend to the right length. Very well made, going to order another set to fix my dad's car.


            Year: 1984 Submodel: Other

            Helpful (0)

          • 4/5

            March 25, 2019

            Flow tubes

            I would have given this 5 stars but had a little trouble getting these to seat right on my H pipe. The flanges came in backwards. If you install just as they come in, in my case anyway, they end up causing and exhaust leak as they dont sit right on the h pipe ball joint. Reversing the flanges is how you get it to sit correctly. Again may have just been in my case but something to look at prior to install. Other great and work perfectly.


            Year: 1991 Submodel: LX

            Helpful (1)

          • 5/5

            March 19, 2019

            Pypes Flow Tube Kit

            They fit as expected. Good if you want to build your own cat-back exhaust for a SN95 Mustang using any brand of muffler and existing tail pipes. Or use as dump system.


            Year: 2004 Submodel: Mach 1

            Helpful (0)

          • 5/5

            March 11, 2019

            Flow tubes

            They seem to work great with the Pypes M80's. But I just had them put on a few hours ago.


            Year: 1997 Submodel: GT

            Helpful (0)

          • 2/5

            March 07, 2019

            Flow tubes

            Flanges hit driveshaft and fuel lines no matter how they are hung either ground clearance issues or chassis clearance


            Year: 1992 Submodel: LX

            Helpful (0)

          • 5/5

            March 03, 2019

            Bolted rite up

            The pieces boleted rite up to factory exhaust and instllaer welded them to 2.5 mufllers with ease.


            Year: 2002 Submodel: GT

            Helpful (0)

          • 5/5

            February 03, 2019

            Gordon 2004GT

            The pypes flow tubes are made 100 better than SLP!! MY SLP FLOW TUBES COME DAMAGED an slp would not do anything about it but American muscle sent me pypes brand flow tubes for no charge I really appreciate!! AM they always take of me no matter what the problem is I will always order my mustang gt parts from American muscle thank you all have a great week!!


            Year: 2004 Submodel: GT

            Helpful (0)

          • 4/5

            December 26, 2018

            Intermediate pipes

            One of the best decisions to purchase. Fit perfect looks great easy install


            Year: 1991 Submodel: GT

            Helpful (1)

          • 5/5

            October 09, 2018

            Perfect fit!

            Bolted right up to the x pipe and lined up with the factory hanger locations.


            Year: 2000 Submodel: V6

            Helpful (1)

          • 5/5

            September 27, 2018

            Stainless flow Tubes

            I was looking piecing together a new exhaust system from different vendors to work with my 1.75" headers for my 94 GT. In looking for Stainless 2.5" flow tubes, these were the only ones I could locate and they were of good quality and came at an attractive cost from a great supplier, American Muscle.


            Year: 1994 Submodel: GT

            Helpful (1)

          • 5/5

            September 01, 2018


            Perfect fit for the X Pipe i bought...getting a set of Flowmaster 40 series mufflers and the new exhaust will be ready to install on my 94 GT


            Year: 1994 Submodel: GT

            Helpful (1)

          • 4/5

            August 27, 2018

            Super easy to install

            The flow tubes are easy to install, they slid right into the pair of m80s I also purchased. Mounts perfectly on stock exhaust. Only gave it a 4 star because it did not come with any hardware, luckily I was able to use existing nuts and bolts.


            Year: 1994 Submodel: Cobra

            Helpful (2)

          • 1/5

            August 14, 2018

            was expecting a better fitment

            End of piping was all bent and beat up probably due to handeling. Does not come with new bolts (not the end of the world but they should) and install shop had to bend them more as they did not fit like they should have. For the cost and the extra work needed to make them work would have been the same as the shop making their own. Fortunately this item does not break the bank but not as discribed. :(


            Year: 1998 Submodel: Cobra

            Helpful (3)

          • 5/5

            August 09, 2018

            A much needed part

            I have an aging mustang with over 200k on the odometer, it needed some exhaust bad. The pipes fit up like stock not a single issue. That and a pypes off road x pipe i bought a long time ago from you folks helps too. Thanks for listening.


            Year: 1998 Submodel: GT

            Helpful (3)

          • 5/5

            August 06, 2018

            Flow tube

            Just what I needed. Worked great on my 92 GT. Thanks American Muscle


            Year: 1992 Submodel: GT

            Helpful (2)

          • 4/5

            July 26, 2018

            Does the job in a pinch

            Shop had to cut to size hense 4 stars. It should have been a perfect fit was a tad long for my setup otherwise they hooked up the flowmaster super 44 with no problems.


            Year: 1992 Submodel: GT

            Helpful (3)

          • 5/5

            May 24, 2018


            was the oerfect replacement for my old pipes, the right fitment and good quality highly recomend for anyone building a custom exhaust


            Year: 2003 Submodel: GT

            Helpful (2)

          • 5/5

            May 18, 2018

            Great fit

            Great fit and placed the muffers perfect with on3 y pipe


            Year: 1990 Submodel: LX

            Helpful (2)

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