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Flowmaster 40 for GMC 2500HD...

Discussion in 'Chevy Trucks' started by mkwl, Apr 27, 2008.

  1. mkwl

    mkwl 2000 Club Member
    Messages: 2,361

    Hey all-

    My girlfriend is getting me a Flowmaster 40 muffler for me truck. My question is, where to get one that will fit, and the right part number? I have two pipes in and 2 pipes out. 2003 GMC Sierra 2500HD RC/LB 6.0L V8 gas.

    Thanks,
    Matt
     
  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Matt you won't find a 40 series that'll "bolt right on" due to the odd spacing of the duel inlets and outlets on your stock setup. You'd need an exhaust shop and several custom made adapters to make it work. If it needs to be a bolt on, you might want to consider spending the extra money on a full cat-back instead of only a muffler.
     
  3. mkwl

    mkwl 2000 Club Member
    Messages: 2,361

    Can it be done- how much would it run to mod it to work? How much would the cat-back run me?
     
  4. PahlsLawnCare

    PahlsLawnCare Junior Member
    Messages: 26

    Personally i would put on the flowmaster 50 series big block. I just put it on my 02 HD with the 6.0 two days ago and so far i love it. Great sound and you can tell theres more power. And they come to fit where your old muffler was and it comes with dual inlet and dual outlet.
     
  5. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Sure it can be done with some custom pipe work...just wont be something you'll be able to install yourself in your driveway. Hard to comment on price, depends on what the shop charges. Figure at least an 1-1 1/2 hrs to make up the adapters and get it all on and connected. Plus whatever they charge for the materials.


    A full mandrel bent Aluminized Flowmaster cat-back kit (with a 40 series) is around $380-$400 depending on where you buy.


    And I agree with PLC, if you go the muffler only/adaptation route, use the 50 series big block muffler over the 40 series. The 40's can be rather loud with annoying interior drone at 35-55 MPH on an HD.
     
  6. mkwl

    mkwl 2000 Club Member
    Messages: 2,361

    So a 50 would be the way to go then. Where's the best place to get one/part # for the one that will fit my truck. Does the 50 still have the "big block" sound? (louder than stock)?
     
  7. mkwl

    mkwl 2000 Club Member
    Messages: 2,361

    Can I put the 50 on my truck myself or would I still have to have a shop so it?
     
  8. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Unless you buy a complete cat-back kit (muffler, front pipe, tail pipe) your going to need an exhaust shop for the install, no matter which muffler you buy.

    And yes the 50's sound good, not obnoxiously loud but will definitely have more sound than the stock exhaust.

    Call Summit Racings, or Jegs tech line, they'll be able to help you find the p/n that would be the most adaptable to your truck.
     
  9. Sydenstricker Landscaping

    Sydenstricker Landscaping PlowSite Veteran
    Messages: 3,882

    I have the big block on my 6.0 It does have a good sound, very, very deep and has a good bark at 3,000 rpm:) You can hear it a little in the cab, but not alot. It isnt loud enough for me though. I want to get the delta 40 under there. One issue, where the heck are you guys finding dual inlet/dual outlet flowmasters? Mine has the dual inlet crap, but single outlet. I couldnt find the dual innie outtie set up at all. Kinda sucks since I wanted to 45 it out on each side behind the rear tires. Nothing better than getting up next to a ahole on their cell phone with the window down, kick it in neutral and hit the loud pedal. I have gotten flipped off a few times for that in the past:D

    As far as install, I got the muffler back kit and if you got a sawzall, some wrenches, a floor jack, 12 pack and 45 minutes, do it yourself. Was very easy to do. Just make sure your cuts are clean and straight. The pipes will slide together easier that way and get a better seal
     
    Last edited: Apr 27, 2008
  10. ABES

    ABES PlowSite.com Addict
    from MN
    Messages: 1,322

    If you look around at summit or jc whitney you can find dual inlet/ outlet mufflers or you can just get 2 mufflers you can fit 2 mufflers side by side thats what ive got now. But im looking to go a little quiter.
     
  11. PahlsLawnCare

    PahlsLawnCare Junior Member
    Messages: 26

    You should be able to find dual inlet and outlet at the flowmaster website flowmastermufflers.com and they have all the mufflers that you can order with different sizes.