The exhaust system in your GMC has been designed to provide for the most efficient flow of the exhaust gasses that leave the engine after the combustion process. Connected to each of the cylinders is one of two GMC headers. They are the first segments of the exhaust system, and they are designed to combine the volume of gas coming from each cylinder into a single volume of air. For maximum efficiency, each cylinder pipe of the GMC headers is of equal length, allowing the backpressure in each cylinder to be consistent. All of the pipes then combine into a larger tube, called a collector pipe. After many years of driving your vehicle, the GMC headers may start to develop holes, and thus, exhaust leaks, due to the natural process of corrosion. When it is time to replace them, you will find a set similar to the original components in our large online catalog, for a very good price. Our GMC headers are direct replacements for the original units, because they are designed to meet the specifications of the stock parts. They are made from high quality metals and can be expected to perform just as well and just as long as did the original GMC headers. Because the amount of exhaust flow directly relates to the overall performance of the engine, adding a set of performance GMC headers is an easy way to get a few extra horsepower out of your vehicle. We stock upgraded versions for many vehicles, in a variety of performance levels and finishes. When you are ready to order a new set of GMC headers, visit our website to use our secure online ordering process, or, if you prefer, you may also place your order by phone, with a toll-free call.