by Mike Mavrigian
(Taken from Performance Exhaust Systems by Mike Mavrigian)
Header Styles Apart from fully custom-designed setups, common header styles include full-length (often called long-tube), shorty (often called block-hugger), lakester, and tri-Y.
Long-tube headers are usually designed with (in the case of an 8-cylinder engine) four primary tubes that merge into a single collector. Long-tube headers are generally designed to favor low-end and mid-range torque.
Shorty headers, as the name implies, feature relatively short primary tubes. Shorties are popular for many hard-to-fit applications with regard to available underhood space and often help ease installation. Short primary tubes tend to favor the upper RPM range, but as a compromise for a street vehicle where space is an issue they remain popular.
Lakester styles are so-named because of their use in early dry lake racing. This style features short primary tubes that immediately enter a long straight megaphone (tapered) style secondary pipe. Lakesters usually feature a cutout plate, allowing you to run through a pipe/muffler system or open, bypassing the rest of the system. This style remains popular for nostalgia/old-school hot rod buffs.
Tri-Y headers are regular headers that have two of the primary pipes merging into adjacent primary pipes (creating a Y intersection). The bank of four primary pipes is relatively short, connecting to a pair of larger-diameter primary pipes, ending with the two larger primary pipes merging into a common collector. The idea behind a Tri-Y design is to create a port separation by pairing the cylinders that are firing 180 degrees apart. Merging the primaries and transitioning into a larger-diameter pipe helps to increase exhaust scavenging. Pulling exhaust gases out more quickly promotes increased air intake, speeding up the combustion process, and theoretically producing more power.
Short headers are often a good choice for universal vehicle applications, from the standpoint of fitment ease and greatly reduced clearance issues to components, such as steering shafts. Shorty headers are often favored for applications such as street rods where space is at a premium. While equal-length primaries help to promote engine efficiency, for the street it’s not a concern.