What are the different tubing options for headers and what is the difference between them?
There are two major designs for headers: the 4-2-1 design and the 4-1 design. In many cases 4-1 headers are designed for racing applications where the car is being driven at or near redline. The 4-1 design maximizes the power, unlike the 4-2-1 evenly distributes it throughout the power band. There are cases where a 4-1 header works better than a 4-2-1 and creates more power in the RPM ranges.
