All Exhaust Systems by Engine Model - Big Block Chevy 454 / 502, 7.4L / 8.2L Exhaust Systems

CMI Fusion Integrated Tailpipe Big Block Chevy Exhaust System

This is the all new, salt water rated "Fusion" Performance Header system from CMI. For years Custom Marine has produced custom exhaust systems for just about every Hi-Performance application.  But now CMI has set their sights on offering an affordable Performance Header system for the entry level Hi-Performance market with the new "Fusion" header system. This new header was designed as an affordable upgrade to exhaust manifold systems for engines needing to support upwards of 600 horsepower, while using standard Mercury Bravo exhaust exit locations. These headers are offered in the "Platinum" series finish which features a brushed satin lower section,  then mating it to a highly polished top tailpipe to produce a striking appearance on any engine. By integrating the tailpipe CMI can reduce costs to the user and eliminate costly clamps and gaskets. Premium 316L stainless steel construction, as well as the patented cool collar exhaust flange make for a durable header that will offer years of trouble free service. While the standard version is designed to fit stock Mercruiser Bravo exhaust exit locations, there are also two custom fit tailpipe options available that will allow the header to be assembled at the factory to your boats specifications. Up to a 2" vertical and/or horizontal correction can be made from the stock locations which allows this header to fit a huge range of options. (Additional charges apply)

Note: This system does not have separate tailpipes. It's pipes are set up for standard Bravo hole locations.

CMI 454/502 Direct Mercruiser Replacement E-Top Exhaust System, Polished

The CMI 454/502 E-Top Header Kit is a a true plug and play system. There is no need to purchase additional custom pipes. These are a direct replacement for your stock 454/502 engine. CMI headers offer more water jacketed protection than your stock exhaust can provide. CMI uses the same high quality semi-automated process on these headers as with the entire product line. These headers are fully post annealed to reduce stresses built up in the header during the manufacturing process. Best of all, 454/502 E-Top headers are made to last, they are mandrel bent and formed from hight quality 316L grade material. There are no parts to crack, all CMI collectors are forged from American made Stainless Steel.

Note: All CMI Systems are sold without Talipipes

CMI 454/502 Direct Mercruiser Replacement E-Top Exhaust System, Satin

The CMI 454/502 E-Top Header Kit is a a true plug and play system. There is no need to purchase additional custom pipes. These are a direct replacement for your stock 454/502 engine. CMI headers offer more water jacketed protection than your stock exhaust can provide. CMI uses the same high quality semi-automated process on these headers as with the entire product line. These headers are fully post annealed to reduce stresses built up in the header during the manufacturing process. Best of all, 454/502 E-Top headers are made to last, they are mandrel bent and formed from hight quality 316L grade material. There are no parts to crack, all CMI collectors are forged from American made Stainless Steel.

Note: All CMI Systems are sold without Talipipes

CMI Merc 500 EFI Replacement E-Top Exhaust System

CMI Elbow Top headers are designed for direct replacement of most stock cast manifolds. Top engine builders and stern drive manufacturers who want to optimize performance of small- or big-block marinized engines prefer CMI Elbow Top headers for their engines. CMI E-Top systems offer separated exhaust passages with long individual exhaust tube runners to minimize cylinder to cylinder influence and improve exhaust gas scavenging, which allows the engine to breathe freely and deliver peak performance power. All CMI Elbow Top Systems include water distribution tubes, cooling water bypass couplings installed on the collector elbow, by-pass hose fittings, attaching cap screws, exhaust port gaskets, hose clamps and cooling water inlet fittings needed for most installations.

Note: All CMI Systems are sold without Tailpipes 

CMI Big Block Chevy E-Top Platinum Exhaust System

CMI Elbow Top headers are designed for direct replacement of most stock cast manifolds. Top engine builders and stern drive manufacturers who want to optimize performance of small- or big-block marinized engines prefer CMI Elbow Top headers for their engines. CMI E-Top systems offer separated exhaust passages with long individual exhaust tube runners to minimize cylinder to cylinder influence and improve exhaust gas scavenging, which allows the engine to breathe freely and deliver peak performance power. Each header features a permanently attached, non-adjustable exhaust tailpipe configured to meet precise specifications for stan¬dard transom layouts and placement of thru-hull exhaust tips. All CMI Elbow Top Systems include rubber water distribution tubes, cooling water bypass couplings installed on the collector elbow, by-pass hose fittings, attaching cap screws, exhaust port gaskets, hose clamps and cooling water inlet fittings needed for most installations.

Note: All CMI Systems are sold without Tailpipes

CMI Big Block Chevy E-Top Polished Exhaust System

CMI Elbow Top headers are designed for direct replacement of most stock cast manifolds. Top engine builders and stern drive manufacturers who want to optimize performance of small- or big-block marinized engines prefer CMI Elbow Top headers for their engines. CMI E-Top systems offer separated exhaust passages with long individual exhaust tube runners to minimize cylinder to cylinder influence and improve exhaust gas scavenging, which allows the engine to breathe freely and deliver peak performance power. Each header features a permanently attached, non-adjustable exhaust tailpipe configured to meet precise specifications for stan¬dard transom layouts and placement of thru-hull exhaust tips. All CMI Elbow Top Systems include rubber water distribution tubes, cooling water bypass couplings installed on the collector elbow, by-pass hose fittings, attaching cap screws, exhaust port gaskets, hose clamps and cooling water inlet fittings needed for most installations.

Note: All CMI Systems are sold without Tailpipes

The picture for this item is shown with a Stainless distribution tree, but this part includes a rubber distribution tree.

CMI Big Block Chevy E-Top Platinum Exhaust System

CMI Elbow Top headers are designed for direct replacement of most stock cast manifolds. Top engine builders and stern drive manufacturers who want to optimize performance of small- or big-block marinized engines prefer CMI Elbow Top headers for their engines. CMI E-Top systems offer separated exhaust passages with long individual exhaust tube runners to minimize cylinder to cylinder influence and improve exhaust gas scavenging, which allows the engine to breathe freely and deliver peak performance power. Each header features a permanently attached, non-adjustable exhaust tailpipe configured to meet precise specifications for stan¬dard transom layouts and placement of thru-hull exhaust tips. All CMI Elbow Top Systems include rubber water distribution tubes, cooling water bypass couplings installed on the collector elbow, by-pass hose fittings, attaching cap screws, exhaust port gaskets, hose clamps and cooling water inlet fittings needed for most installations.

This Kit includes an upgrade to a Stainless Steel Water Distribution Tree.

Note: All CMI Systems are sold without Tailpipes

CMI Big Block Chevy E-Top Polished Exhaust System

CMI Elbow Top headers are designed for direct replacement of most stock cast manifolds. Top engine builders and stern drive manufacturers who want to optimize performance of small- or big-block marinized engines prefer CMI Elbow Top headers for their engines. CMI E-Top systems offer separated exhaust passages with long individual exhaust tube runners to minimize cylinder to cylinder influence and improve exhaust gas scavenging, which allows the engine to breathe freely and deliver peak performance power. Each header features a permanently attached, non-adjustable exhaust tailpipe configured to meet precise specifications for stan¬dard transom layouts and placement of thru-hull exhaust tips. All CMI Elbow Top Systems include rubber water distribution tubes, cooling water bypass couplings installed on the collector elbow, by-pass hose fittings, attaching cap screws, exhaust port gaskets, hose clamps and cooling water inlet fittings needed for most installations.

This Kit includes an upgrade to a Stainless Steel Water Distribution Tree.

Note: All CMI Systems are sold without Tailpipes

CMI 520 E-Top Satin Exhaust Header System

• Increases in Horsepower up to 31 HP
• Direct replacement – works with existing exhaust outlets
• Improved mid-range acceleration and torque
• Polished and satin finish available
• Patented “Cool Collar” design
• Mandrel bent and formed from high quality 316L grade stainless steel

CMI 520 E-Top Polished Exhaust Header System

• Increases in Horsepower up to 31 HP
• Direct replacement – works with existing exhaust outlets
• Improved mid-range acceleration and torque
• Polished and satin finish available
• Patented “Cool Collar” design
• Mandrel bent and formed from high quality 316L grade stainless steel

CMI Big Block Chevy Standard Bravo Sport Tube Exhaust System, Polished

CMI Sport Tubes are a superior long tube header designed for both racing or virtually any high-performance application. For big- and small-block applications where maximum scavenging and horsepower are required, CMI Sport Tube headers deliver peak performance and power from naturally aspirated engines that generate more than one horsepower per cubic inch of displacement.

The all polished Sport Tube system is offered with a range of exhaust tailpipe options, as well as CMI's Sound Choice™ selectable silencing system. Each system includes all header attaching bolts, gaskets and cooling fittings required for installation.

Note: All CMI Systems are sold without Tailpipes

CMI Big Block Chevy Sport Tube Exhaust System, 6" Taller, Polished

CMI Sport Tubes are a superior long tube header designed for both racing or virtually any high-performance application. For big- and small-block applications where maximum scavenging and horsepower are required, CMI Sport Tube headers deliver peak performance and power from naturally aspirated engines that generate more than one horsepower per cubic inch of displacement.

The all polished Sport Tube system is offered with a range of exhaust tailpipe options, as well as CMI's Sound Choice™ selectable silencing system. Each system includes all header attaching bolts, gaskets and cooling fittings required for installation.

Note: All CMI Systems are sold without Tailpipes

CMI Big Block Chevy Sport Tube Exhaust System, 9" Taller, Polished

CMI Sport Tubes are a superior long tube header designed for both racing or virtually any high-performance application. For big- and small-block applications where maximum scavenging and horsepower are required, CMI Sport Tube headers deliver peak performance and power from naturally aspirated engines that generate more than one horsepower per cubic inch of displacement.

The all polished Sport Tube system is offered with a range of exhaust tailpipe options, as well as CMI's Sound Choice™ selectable silencing system. Each system includes all header attaching bolts, gaskets and cooling fittings required for installation.

Note: All CMI Systems are sold without Tailpipes

Powerflow Big Block Kit with Stainless Riser

This "A" pipe is used with Bravo drives or King Cobra drives. It's short design allows for thru transom exhaust tip hook-up. This system has a 10% horsepower increase and 40-50 foot pounds of torque on stock engines. All Powerflow systems are available fully polished.

Powerflow manifolds are manufactured using the finest materials and most advanced techniques available. The high quality aluminum manifold castings feature water jackets that surround each exhaust passage, including the port, to eliminate the possibility of burn out.

 The outside manifold surfaces are then coated with the highest quality epoxy powder coating available, creating a part that not only is highly corrosion resistant, but good looking as well. Features an external fitting to accept stock MerCruiser thermostat plumbing.

Powerflow Big Block System with Stainless Silent Choice Risers

This popular system allows the use of a switchable exhaust diverter. These risers are stainless steel and custom designed to ease installation. They use a standard 4" diverter connection.

Powerflow manifolds are manufactured using the finest materials and most advanced techniques available. The high quality aluminum manifold castings feature water jackets that surround each exhaust passage, including the port, to eliminate the possibility of burn out.

 The outside manifold surfaces are then coated with the highest quality epoxy powder coating available, creating a part that not only is highly corrosion resistant, but good looking as well. Features an external fitting to accept stock MerCruiser thermostat plumbing.

Powerflow S-Pipe System - Big Block System Chevy with Stainless Risers

This "S" pipe is unique in many ways. It has an infinite number of advantages. This pipe will size up to many pre-existing port locations. It's great for below platform applications with large camshafts or high performance motors. It allows the exhaust to mix with water down at the first connection.

Powerflow manifolds are manufactured using the finest materials and most advanced techniques available. The high quality aluminum manifold castings feature water jackets that surround each exhaust passage, including the port, to eliminate the possibility of burn out.

 The outside manifold surfaces are then coated with the highest quality epoxy powder coating available, creating a part that not only is highly corrosion resistant, but good looking as well. Features an external fitting to accept stock MerCruiser thermostat plumbing.

Powerflow Plus System - Black manifolds and risers - 30 degree

IMCO's totally new Powerflow Plus cast aluminum, fully water-jacketed exhaust manifolds are available in black or polished. Black manifolds and risers are hard-coat anodized inside and out to withstand the tough marine environment. The new Powerflow Plus featuresIMCO's innovative patented design with 33" internal runners and a new ultra hi-flow exhaust riser. Brackets are available for this system.

Powerflow manifolds are manufactured using the finest materials and most advanced techniques available. The high quality aluminum manifold castings feature water jackets that surround each exhaust passage, including the port, to eliminate the possibility of burn out.

The outside manifold surfaces are then coated with the highest quality epoxy powder coating available, creating a part that not only is highly corrosion resistant, but good looking as well. Features an external fitting to accept stock MerCruiser thermostat plumbing.

Powerflow Plus System - Black manifolds and risers - 85 degree

IMCO's totally new Powerflow Plus cast aluminum, fully water-jacketed exhaust manifolds are available in black or polished. Blackmanifolds and risers are hard-coat anodized inside and out to withstand the tough marine environment. The new Powerflow Plus features IMCO's innovative patented design with 33" internal runners and a new ultra hi-flow exhaust riser. Brackets are available for this system.

Powerflow manifolds are manufactured using the finest materials and most advanced techniques available. The high quality aluminum manifold castings feature water jackets that surround each exhaust passage, including the port, to eliminate the possibility of burn out.

The outside manifold surfaces are then coated with the highest quality epoxy powder coating available, creating a part that not only is highly corrosion resistant, but good looking as well. Features an external fitting to accept stock MerCruiser thermostat plumbing.

Powerflow Plus System - Polished manifolds and risers - 30 degree

IMCO's totally new Powerflow Plus cast aluminum, fully water-jacketed exhaust manifolds are available in black or polished. Black manifolds and risers are hard-coat anodized inside and out to withstand the tough marine environment. The new Powerflow Plus features IMCO's innovative patented design with 33" internal runners and a new ultra hi-flow exhaust riser. Brackets are available for this system.

Powerflow manifolds are manufactured using the finest materials and most advanced techniques available. The high quality aluminum manifold castings feature water jackets that surround each exhaust passage, including the port, to eliminate the possibility of burn out.

 The outside manifold surfaces are then coated with the highest quality epoxy powder coating available, creating a part that not only is highly corrosion resistant, but good looking as well. Features an external fitting to accept stock MerCruiser thermostat plumbing.

Powerflow Plus System - Polished manifolds and risers - 85 degree

IMCO's totally new Powerflow Plus cast aluminum, fully water-jacketed exhaust manifolds are available in black or polished. Black manifolds and risers are hard-coat anodized inside and out to withstand the tough marine environment. The new Powerflow Plus features IMCO's innovative patented design with 33" internal runners and a new ultra hi-flow exhaust riser. Brackets are available for this system.

Powerflow manifolds are manufactured using the finest materials and most advanced techniques available. The high quality aluminum manifold castings feature water jackets that surround each exhaust passage, including the port, to eliminate the possibility of burn out.

 The outside manifold surfaces are then coated with the highest quality epoxy powder coating available, creating a part that not only is highly corrosion resistant, but good looking as well. Features an external fitting to accept stock MerCruiser thermostat plumbing.