Slight correction. They replace the exhaust manifold.slimm44 said:connect the exhaust manifold to the exhaust.
A stock exhaust manifold dumps the exhaust into a single pipe immediately and thus creates back pressure which inhibits the ability of the exhaust gases to exit the cylinder. The idea behind an exhaust header is to eliminate the manifold's back pressure. Instead of a common manifold that all of the cylinders share, each cylinder gets its own exhaust pipe. These pipes come together in a larger pipe called the collector. On some headers, the individual pipes are cut and bent so that each one is the same length as the others. By making them the same length, it guarantees that each cylinder's exhaust gases arrive in the collector spaced out equally so there is no back pressure generated by the cylinders sharing the collector.vjraw said:What are headers and what are they for?