Exhaust Header for 2004-2005 Chevrolet Impala Monte Carlo 3.8L L67 V6

What's in the box: Stainless Steel Racing Header Mounting hardware, bolts and gaskets Product Feature: Made of High-Quality T304 Stainless Steel Material TIG Welded CNC Machine Flange 6-2-1 High-Performance Racing Spec. Design O2 Sensor Insertion and Metal Gasket Included Increase High Flow Air, Instantly Gain 10 -15 Hp. / Tq. Specifications: Brand Name: FLASHARK Certificate: ISO9001:2000 Application: Automobile Exhaust Header Material: Stainless Steel Surface: Mirror Polish Outlet Size: 3.00", Primary Tube Size: 1.50" Number of o2 Locations: 2 Head Flange Thickness: 7/16" Outlet Flange Thickness: 3/8" Exhaust Header VS Manifold, which is the better choice? The structural differences between exhaust headers and manifolds are the material and size. From the material, exhaust headers are made of lighter, thinner steel, while exhaust manifolds are made of thick iron. Exhaust headers are also longer than exhaust manifolds. When in use, exhaust manifolds create back pressure, which lowers performance. Because each cylinder of the engine is given its own tube, however, headers eliminate this problem; thus, allowing the gases to exit without the creation of back pressure. Therefore, exhaust headers are a BETTER choice than an exhaust manifold. Replacing or upgrading your exhaust header is necessary for both engine performance and sound. Whether on or off the track, exhaust headers provide more horsepower and improved exhaust sound. FLASHARK offers many products to help you create your own custom engine headers. It's really easy and convenient to use: direct bolt-on, no modification needed.