CMI Marine Headers: CMI Marine Headers

High Performance Custom Marine Inc CMI Headers & Tailpipes:

West Coast Offshore carries all the CMI Headers & Tailpipe Systems including CMI Big Tube Headers, CMI Big Elbow Top Race Headers, CMI Sport Tube Headers, CMI 496 Sport Tube Performance Headers, CMI Elbow Top (E-Top) Headers, CMI 496 Elbow Top (E-Top) Headers, CMI 520 Headers, CMI Gen-X Headers, CMI Evo-X Headers, and CMI Small Block Headers.

More About CMI Headers & Tailpipes:

All Custom Marine Inc (CMI) Headers are built according to strict standards that have elevated them as the top choice for performance boaters and offshore racers that demand on-the-water performance.

CMI headers begin their life being manufactured with state-of-the-art materials such as 316L and 317L stainless steel, which offers superior durability and corrosion-resistance. A unique and patented process for bending the tubes assures uniform thickness throughout the walls and eliminates all rippling and crazing of the tubes during their production. Heat treating the complete manifold, following its assembly by semi-automated tungsten inert gas welding, greatly reduces internal stresses and imperfections that most commonly cause corrosion, fatigue, and premature failure during high performance applications.

CMI also manufactures custom tailpipes to complement its header systems, as well as exhaust accessories, and integral mufflers for almost any single, dual, triple or quad engine configuration – including but not limited to small block or big block applications, Chevrolet and Buick V-6s and Ford 460 and SVO's.

With Custom Marine Inc, high performance boaters receive a combination of reliability and performance unrivaled by any competitor’s products available on the market.

“It's all about Performance.” Custom Marine Inc.

Choose the Right CMI Headers for your needs:

Custom Marine CMI Choose Right Headers Image

CMI Sport Tube Headers

CMI Sport Tube headers are the best designed long-tube header system for practically any high-performance or racing application. CMI Sport Tube headers provide top power and performance from naturally aspirated big and small block engines generating more than one horsepower per cubic inch of displacement.

Fully polished CMI Sport tube systems are compatible with a wide range of exhaust tailpipes as wall as the “Sound Choice” selectable silencer. All CMI Sport Tube header systems come with header bolts, gaskets, and any cooling fittings that may be required for installation.

4.5” Outside-Diameter Tailpipe is required and sold separately.

CMI Big Tube Headers

CMI Big Tube Header Systems give big block engines that have 540 or more cubic-inch displacements the ability to generate peak horsepower and torque during the whole operating range. CMI Big Tube Headers have helped power more National and World Champion boats than any of the other header manufacturers combined, proving they can withstand some of the toughest marine environments encounterable – offshore racing. CMI Big Tubes can be stepped in any custom configuration to comply with any engine builders’ needs.

The largest inside diameter options available on the marine header market are offered with CMI’s fully polished Big Tube systems, including 2 1/8”, 2 1/4”, and 2 3/8” inside diameters for all possible step combinations. All CMI Big Tube header systems come with stainless steel cooling fluid distribution tubes, header bolts, gaskets, and any cooling fittings that may be required for installation.

CMI also offers a large range of marine exhaust tailpipe options like CMI Sound Choice selectable silencing system to complete any header installation.

CMI Tailpipes sold separately.

CMI Elbow Top Headers

CMI Elbow Top Headers are direct-replacement headers designed for most stock cast manifolds. The best stern drive manufacturers and engine builders wanting to optimize performance of small and big block marine engines prefer CMI Elbow Top (E-Top) Headers for their engines more than any other brand.
CMI E-Top Header Systems offer separated exhaust passages and long individual exhaust tube runners that minimize cylinder to cylinder influence while improving exhaust scavenging, which allows the engine to breathe more freely as well as generate the most power. Every header features a non-adjustable, permanently attached, exhaust tailpipe configured to meet exact specifications for standard transom layouts and thru-hull exhaust tip placements.

All CMI Elbow Top Header system include rubber water distribution tubes, cooling water inlet fittings, cooling water bypass couplings on the collector elbow, hose fittings for bypassing, cap screws, gaskets for exhaust ports, and hose clamps needed for almost any installation.

CMI Elbow Top Systems may be purchased with Stainless Steel distribution tube upgrade.
Standard CMI Elbow Top systems can be ordered with a wide range of CMI Tailpipes or CMI “Sound Choice” selectable silencer system

CMI Fusion Headers

CMI Fusion Headers features polished elbow collector and tailpipes attached to satin finished primary tubes. CMI Elbow Top Headers are direct-replacement headers designed for most stock cast manifolds. The best stern drive manufacturers and engine builders wanting to optimize performance of small and big block marine engines prefer CMI Fusion Elbow Top Headers for their engines more than any other brand.
CMI Fusion Header Systems offer separated exhaust passages and long individual exhaust tube runners that minimize cylinder to cylinder influence while improving exhaust scavenging, which allows the engine to breathe more freely as well as generate the most power. Every header features a non-adjustable, permanently attached, exhaust tailpipe configured to meet exact specifications for standard transom layouts and thru-hull exhaust tip placements.

All CMI Fusion Elbow Top Header system include rubber water distribution tubes, cooling water inlet fittings, cooling water bypass couplings on the collector elbow, hose fittings for bypassing, cap screws, gaskets for exhaust ports, and hose clamps needed for almost any installation.

CMI Fusion Elbow Top Systems may be purchased with Stainless Steel distribution tube upgrade.
Tailpipes are not required for CMI Fusion Header Systems.

Designed for engines generating up to 750 HP
Standard versions designed to fit stock Mercury bravo exhaust exit locations
*** custom fit applications also available ***
Performance gains in Horsepower and Torque
Integrated Tail eliminates tailpipe clamps and gaskets
Features satin primary tubes and a polished elbow collector fused with a polished tailpipe
316L stainless steel offers supreme durability