Generating the most power possible from a marine engine is a challenge every performance boater faces, whether you’re competing on the race circuit or simply enjoying a day on the water with friends.

Anatomy of a Header

Custom Marine headers are made from high-quality 316L and 317L stainless steel tubes and heat treated (annealed) for added stress relief and superior durability.  All CMI headers are hand-welded and polished by skilled artisans who are proud of the top-quality exhaust systems they build.  Every CMI exhaust system is designed to deliver the highest level of quality and peak on-water performance every CMI customer demands.

See ALL Headers
Headers
Outer Tube Tailpipe Jumper Flex Flare Hot Section Cool Air Collar Primary Tube Water Distribution Tube

Outer Tube

Tailpipe Jumper

Flex Flare

Hot Section

Cool Air Collar

Primary Tube

Water Distribution Tube

If you are looking for a marine header, Custom Marine has it.

Below are some of our most popular header styles. Beyond E-Tops, Sport Tubes and Big Tubes, CMI also offers custom headers for Ford, Chrysler and any other platform. All headers are offered in either a polished or satin (brushed stainless) finish and are post annealed. Most common are 316L inner and outer tubes, but we also offer headers in Duplex stainless, Inconel and titanium.

Custom Marine has headers for your small single engine set, up to the wildest quad engine layout. If you can dream it, we can build it. From one off prototypes to high-volume runs, Custom Marine has a solution for every application.

Although CMI is known for water jacketed “eye candy,” we also have vast experience in the off-road market. If you are busing a Sand Car or a Trophy truck, CMI can help. Your options are endless at Custom Marine. Let’s get started today!

Contact Custom Marine today about header options for you!

Header Styles

gen_x_headers

Replacements for stock 525EFI – 700sci Mercury racing engines

496_headers

Direct MerCruiser replacement for 496 Mag or 496 HO engine

elbow_top_systems

Separate exhaust passages with long individual exhaust tube runners minimize cylinder-to-cylinder influence and improve exhaust gas scavenging

sport_tube_systems

Long tube headers that deliver peak performance and power from any naturally aspirated engine

taller_mercury_replacements

Replacements for taller, leaned in or leaned out 525EFI – 700sci Mercury racing engines

big_tube_systems

2 1/8-, 2 ¼-, and 2 3/8-inch inside diameters with long tubes for all big power applications, either naturally aspirated or supercharged

big_elbow_top_race_systems

2 1/8-, 2 ¼-, and 2 3/8-inch inside diameters for all big power applications, either naturally aspirated or supercharged

evo_x_headers

Stainless steel long tube header for Mercury QC4 Turbo engines

small_block_headers

Direct Mercury LT replacements and late model LS configurations