By Mike Mavrigian
The choice of using tubular exhaust headers in place of a cast iron exhaust manifold has become a “no brainer” for just about any performance engine. Most consumers automatically assume that they need headers to complete the build, often without any consideration of the reason. Aside from the obvious appearance aspect, the use of individual-cylinder tubular headers is to promote exhaust gas flow and scavenging (pulling the exhaust out of the cylinder to promote increased intake and exhaust flow).
Rather than serving simply as outlet paths for the exhaust, properly selected headers for a given application can and will increase engine efficiency (power and torque). Properly selected primary tube diameter and length can have an enormous impact on performance.
Tubular headers allow us to more efficiently scavenge exhaust gas and pressure from each cylinder, rather than simply dumping the exhaust into a common manifold. The goal is to reduce backpressure while promoting a “pull-through” of the exhaust gas.
– Excerpted from Hotrod & Restoration, November 2013. Click here to read the complete article in the Digital Version of the November issue.