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  1. #1

    Default Two mufflers on one catalyic converter

    I just got a 11 silverado 1500 and am looking to put an exhaust on it. I went to the local muffler shop and they said they could give me dual single in/out flow 40's. I'm assuming that they are going to put both mufflers on my original cat converter. Is this normal and if the shop does plan on putting both muffler's on one cat should I go ahead with it? Or should I go with one flow single in/dual out?

  2. #2


    I had my Flowmaster Super 40 series dual in/dual out so it's true dual and i love it i would just run to straight pipes and add a dual flowmaster instead of 2 of them man. I also installed a x pipe that helps some with power and evening out the flow of the exhaust..

    2008 Chevy Silverado Ext. Cab Lt Z71 5.3 V8
    7.5 Inch Rough Country Suspension Lift
    RBP Replica Grille Black w Chrome Rivets
    Recon Smoked Cab Roof Lights
    N-Fab Powdercoated Gloss black Cab Length Nerf Steps
    5% Tint over 20% all the way around / 5% Eyebrow Strip
    AVS Smoked Window Visors
    Z71 Stickers Black & Metallic Silver
    Tow Mirrors / Smoked Turn Signals
    XM Satellite Radio Fin / Color Matched
    Interior Plastic Pieces / Color Matched
    Power Acoustic Tweeters
    Painted Bowties / Color Matched
    Painted Door Handles / Color Matched
    Smittybilt Bull Bar / Color Matched
    Custom Rolled Edge Exhaust Tips / Color Matched
    Custom 2.5 Inch Cat Back True Dual Exhaust
    Flowmaster Super 40 Series Dual in / Dual out
    Magnaflow Tru-X Pipe
    K&N Air Filter
    18x9 Rockstars Machined Black
    Center Caps / Color Matched
    33.13.50 Nitto Terra Grapplers
    New Front Wheel Well Liners
    Eagle Eye Black L.E.D. Tailights
    Eagle Eye Black L.E.D. Third Brake Light / Smoked
    Eagle Eye Black L.E.D. Halo Projector Headlights
    Notto HID Kit 10,000k Low beams
    Recon L.E.D. Light Bar
    Buschwacker OE Style Tailgate Cap
    AMI Gloss Black Antenna
    Debadged Chrome Lettering
    Door Molding Removed

  3. #3


    Welcome to the club. Your truck has DUAL CATS that flow into one muffler with one exit. Most likely there going to cut the "Y" pipe off behind the cats and run a muffler with dual inlets/outlets or put dual single in/out mufflers on. With the dual mufflers they stand them on there sides so there enough room. Hope I explained that so you understand.

  4. #4


    Yes they do have 2 cat's and will be ran exactly how SILVERADOTRAILBLAZER said and can have them dual in single out or true dual's either with just one muffler..

  5. #5


    Thanks for the responses guys. I could be wrong, but I looked underneath the truck and I thought that it only came with one cat stock. It looked as though there was a y-pipe coming off each side of the headers and into one cat then the single muffler/exhaust system. What doe you guys think would have a nicer rumble dual in/out flow like what Rockstarrchevy81 is running or two single in/out flows?

  6. #6


    Wouldn't true duals be two completely separate, non-connected exhaust systems? One for each side of the engine?
    When you hear hoofbeats, look for horses not zebras.

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