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Pypes Catted H-Box Mid-Pipe (99-04 GT)

Item 387279
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Ship to: Ashburn - 20149
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      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • Increases Power
      • Deeper, Muscle Car Rumble
      • H-Box Center Chamber Design
      • Full Tig-Welded and Mandrel-Bent
      • 2.5" 409 Stainless Steel Tubing
      • High Flow Ceramic Catalytic Converters
      • 49 State Street Legal
      • Fits 1999-2004 GT Mustangs


      More Power. Add more horsepower and torque to your 1999-2004 GT Mustang by replacing those power robbing factory catalytic converters with a brand new Pypes Catted H-Box. The Pypes Catted H-Box is designed to offer increased horsepower and torque, as well as an even deeper sound dimension, when compared to your traditional H-pipe upgrade.

      Deeper Rumble. This free flowing Pypes H-Box for the 4.6L New Edge GT will not only increase power as a result of its perforated H design within the center chamber and the included ceramic catalytic converters, but it will also add a deep muscle car rumble to the sound of your exhaust.

      Durable, Stainless Steel Construction. Pypes utilizes high quality 16 gauge 409 stainless steel mandrel bent 2.5" tubing for increased exhaust flow and features fully Tig-welded reinforcement plates for additional strength. The included High Flow Ceramic Catalytic Converters far outperform the restrictive stock cats to provide a significant increase in horsepower and torque.

      Application. This Pypes Catted H-Box Mid-Pipe is designed as a direct installation for the 1999-2004 4.6L GT Mustangs, with either aftermarket short tube headers or the stock manifolds and a dual catback exhaust installed. Some cutting required for installation.

      Note. This H-Box Mid-Pipe is 49 State Legal - not Legal in CA - and is not CARB Certified. Please check your local and state ordinances for installation and usage regulations.

      Technical Note: 2004 Mustangs require the use of 24" O2 sensor plug-in extender wires.

      Fitment: 1999 2000 2001 2002 2003 2004 Details

      Pypes HFM37

      CA Residents: WARNING: Cancer and Reproductive Harm -

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) H-Box
      • (2) Down Pipes
      • (1) Down Pipe Sleeve
      • (2) Catalytic Converters
      • (4) Clamps

      Tech Specs

      Mid Pipe Specifications
      Style Mid Pipe: Standard Length H-BoxType Headers Required:Shorty Headers or Stock Manifolds
      Piping Material:409 Stainless SteelPiping Size:2.5"
      Catalytic Converter:Yes - CeramicFitment:1999-2004 GT Mustangs

      Customer Reviews (100+)

        Reviews of Pypes Exhaust products have an average rating of 4.5 out of 5

          Questions & Answers

          10 More Questions

          Will It Fit My Mustang

          • GT - 99, 00, 01, 02, 03, 04