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

• Standard Manifold is powder-coated for corrosion protection
• Optional "Ocean Series" Extreme Corrosion Treatment available for additional interior corrosion protection 
  
• 356T Aluminum Heat treated tubular style cast internal manifold core for header like performance
• Silent choice, captains call, and select sound exhaust diverter system compatible
  
• Sold in pairs
• No tailpipes included, replacement manifolds only!

• Manifold is powder-coated for corrosion protection
• Optional "Ocean Series" Extreme Corrosion Treatment available for additional interior corrosion protection 
• Perfect for use on OEM engines up to 415HP 
• Polished Stainless steel tailpipe is manufactured from premium 316L Stainless steel, 4" OD 
• 356T Aluminum Heat treated tubular style cast internal manifold core for header like performance
• Silent choice, captains call, and select sound exhaust diverter system compatible
• Kit includes all bolts and gaskets needed for installation
• Risers include O2 Sensor bungs and plugs.
• Sold in pairs

• Manifold is powder-coated for corrosion protection
• Optional "Ocean Series" Extreme Corrosion Treatment available for additional interior corrosion protection 
• Perfect for use on performance OEM engines up to 450HP 
• XL Riser for performance applications
• Polished Stainless steel tailpipe is manufactured from premium 316L Stainless steel, 4" OD 
• 356T Aluminum Heat treated tubular style cast internal manifold core for header like performance
• Kit includes all bolts and gaskets needed for installation

• Manifold is powder-coated for corrosion protection
• Optional "Ocean Series" Extreme Corrosion Treatment available for additional interior corrosion protection 
• Perfect for use on HP500, 540 Bulldog and other HP Bravo Applications.
• HP Riser for high performance performance applications.
• Polished Stainless steel tailpipe is manufactured from premium 316L Stainless steel, 4" OD 
• 356T Aluminum Heat treated tubular style cast internal manifold core for header like performance
• Kit includes all bolts and gaskets needed for installation

• Manifold is powder-coated for corrosion protection
• Optional "Ocean Series" Extreme Corrosion Treatment available for additional interior corrosion protection 
• Perfect for use on OEM engines up to 415HP 
• 3" taller riser for tall riser applications
• Polished Stainless steel tailpipe is manufactured from premium 316L Stainless steel, 4" OD 
• 356T Aluminum Heat treated tubular style cast internal manifold core for header like performance
• Silent choice, captains call, and select sound exhaust diverter system compatible
• Kit includes all bolts and gaskets needed for installation

• Manifold is powder-coated for corrosion protection
• Optional "Ocean Series" Extreme Corrosion Treatment available for additional interior corrosion protection 
• Perfect for use on OEM engines up to 415HP 
• 6" taller riser for tall riser applications
• Polished Stainless steel tailpipe is manufactured from premium 316L Stainless steel, 4" OD 
• 356T Aluminum Heat treated tubular style cast internal manifold core for header like performance
• Silent choice, captains call, and select sound exhaust diverter system compatible
• Kit includes all bolts and gaskets needed for installation

• Manifold is powder-coated for corrosion protection
• Optional "Ocean Series" Extreme Corrosion Treatment available for additional interior corrosion protection 
• Perfect for use on performance OEM engines up to 450HP 
• Riser designed for Jet boat performance applications or boats with a crank centerline style exhaust exit
• Polished Stainless steel tailpipe is manufactured from premium 316L Stainless steel, 4" OD 
• 356T Aluminum Heat treated tubular style cast internal manifold core for header like performance
• Kit includes all bolts and gaskets needed for installation

• Manifold is powder-coated for corrosion protection
• Optional "Ocean Series" Extreme Corrosion Treatment available for additional interior corrosion protection 
• Perfect for use on performance OEM engines up to 450HP 
• Low Port Riser for below platform or other low exit applications
• Polished Stainless steel tailpipe is manufactured from premium 316L Stainless steel, 4" OD 
• 356T Aluminum Heat treated tubular style cast internal manifold core for header like performance
• Kit includes all bolts and gaskets needed for installation

With the overwhelming success of the performance of Seaward exhaust manifold system it was only natural to expand into even more offerings. This latest version uses the popular Seaward Ocean Series manifolds combined with a intersecting companion pipe allow for direct replacement of rotting, cracked, failing original elbow top styled headers while providing the unmatched durability of a performance manifold system. This system allow's the original tailpipes to be reused for simplicity and affordability of exhaust replacement.

• Manifold is powder-coated for corrosion protection
• Optional "Ocean Series" Extreme Corrosion Treatment available for additional interior corrosion protection 
• HP Riser for high performance performance applications.
• CMI Flange on riser uses existing tailpipes.
• Also replaces Mercury HP 500 EFI applications. 
• Polished Stainless steel tailpipe is manufactured from premium 316L Stainless steel, 4" OD 
• 356T Aluminum Heat treated tubular style cast internal manifold core for header like performance
• Kit includes all bolts and gaskets needed for installation

Custom Measurements
Mercury Standard Exhaust Hole Locations

With the overwhelming success of the performance of Seaward exhaust manifold system it was only natural to expand into even more offerings. This latest version uses custom built dry tailpipes for a purpose built custom exhaust system.

Dry tailpipes refers to tailpipes that are water jacketed all the way towards the end of the tailpipe. This eliminates water mixing with the exhaust stream and causing "reversion" scenarios. This solid tailpipe design runs all the way through the transom and terminates approximately 5" outside the boats transom. A water discharge bung is provided in the top of the tailpipe inside of the transom and requires a separate water dump line and exit fitting. ***The line, fitting, and discharge fittings are sold separate.

These style of tailpipes require transom sealing rings that are again sold separately. Here is an example of what is commonly used 620-906700.

The Seaward exhaust systems will be the biggest market changing product to debut in 2016. These exhaust systems were not only created using the most modern robotic electronic machine operations but with state of the art tooling. What does all of this mean? It means you can now buy the very best reliable performance exhaust manifold system that money can buy for a whole lot less money.

Hardin looked at the exhaust market in the same fashion the worlds top manufacturers have in that through the most modern state of the art design and production efficiency we could build the best product and reduce the overall cost by hundreds of dollars over anything even remotely comparable in the world today

The SEAWARD debut is a 100% all new design these exhaust systems were built to provide virtually every feature once desired in a performance marine exhaust system with reliability and longevity being the key features.

Here's the facts: There is no other performance exhaust manifold system on the market today that with as many features and advancements in construction PERIOD. Starting with a 356T Heat treated tubular style cast internal core that has been optimized to flow with the technology design and shape and design of a tubular header. By extending the runners and separating the exhaust pulses to the collector this system produces maximum power in a compact design.

More Facts: 1000 hour salt spray coating. That's right this industry has never seen these types of processes. These products are extending the naval and aerospace program products as much as ten years. Sure the finish is that of a show piece, but it's truly what you can't see that sets these systems apart. Underneath the thick non-porous billet heat treated aluminum casing lies the most exceptional foundation of corrosion protection found anywhere. A hydrogen infused zinc process is applied to each manifold. Until now salt spray testing could merely only withstand 100-150 hours of sustained exposure, Today those numbers are 1000 hours of durability.

More facts: Tailpipes --- Not all are created equal --- Beauty is well beyond skin deep here as the beautifully polished stainless steel exhaust risers of the systems are manufactured from 316L Stainless Steel while inferior systems choose inferior stainless (303/304 Auto Grade) steel, Seaward systems offer nothing but the best money can buy which has been proven to be the most durable long lasting product for marine use.

The new Seaward System bears all of the superior quality's of their standard seaward system with the addition of a companion tailpipe allowing the connection of the factory tailpipe already in use. This is the perfect solution for engines equipped with silent choice or custom tailpipes as the user can still retain those. each kit comes complete with all necessary hardware for a complete installation.

FITS: Custom Big Block Chevy Dry Tailpipe applications.

NOTE: This system is ***STANDARD BRAVO EXIT LOCATION ONLY*** All others are built by quote only! Contact us for a quote.

***NOTE*** Modified engines often have different deck heights and raised exhaust ports with aftermarket cylinder heads. These tailpipes must be confirmed using this measurement sheet.

Cyclone "Shorty Headers"
Replacement Header For Gil Marine, Mercury Hi-Performance & Rex Power Torque Manifolds
Fully Polished Finish

Do your performance manifolds look like these but your stainless steel tailpipes still look like jewelry?  This is a common problem with a number of aftermarket high performance exhaust manifolds, the solution is to replace them with the Cyclone "Shorty"! An all 316L stainless steel header designed as a direct bolt-on replacement for your cast aluminum manifolds. 

By retaining your existing stainless steel tailpipe or riser, you can remove your existing manifolds and simply slide the new "Shorty Header" into place and connect your existing tailpipes.  These units are currently available to replace Mercury Hi-Performance, Gil Marine, and Rex Marine Power Torque manifolds.  Each header is manufactured to the highest quality standard using 100% 316L stainless steel construction, laser machined flanges for a perfect gasket seal, and exhaust tubes that are B.T.B. bent to exact tolerances every time.  A fully welded computer designed water inlet manifold assures equal water flow to each individual exhaust tube.  These headers are completely annealed to maximize durability while preventing corrosion.  CAD-5 technology was used to develop the staggered length exhaust tube runners which provide for broader low and mid range torque, while yielding incredible peak power. This kit comes complete with all necessary bolts and gaskets to attach to your engine. Riser gaskets are not included, and you may need up to 4 gaskets depending on application. See related parts.

Cyclone Water Jacketed Header System For GM Big Block Standard Dimension Bravo - Fully Polished

This Cyclone wet exhaust series header works perfectly on both stock and modified performance applications This header mixes engine cooling water with the exhaust near the end of the tailpipe That allows you to use a 4" rubber hose connection to attach your transom mounted exhaust tips This is the perfect replacement for your factory exhaust system. Oil filter bracket, shift control bracket, and ECU bracket not included. Gaskets and bolts are included.

If you are one of thousands of performance boaters seeking the power and styling from stainless steel tubular headers then you're looking at the leader in exhaust technology These "Cyclone" header systems share 100% 316L stainless steel construction. All appropriate flanges are laser cut and CNC machined for a perfect gasket seal. Each individual exhaust tube is bent to precise, exact tolerances every time. A computer designed fully welded water inlet manifold provides equal water distribution to each exhaust runner tube. While each set of headers goes through a 1900 degree annealing process that multiplies the durability factor of the header many times over while providing added protection against corrosion. But the heart of these systems lies in the ability to generate loads of additional power. By using CAD-5 Technology to develop a unique staggered tube runner length, these systems are capable of maximizing the broadest low end and midrange torque, all the while yielding incredible peak power gains. These systems are available in many configurations to fit every boaters needs. Rest assured when you lay down your hard earned money because the system comes complete with all necessary mounting bolts and gaskets making installation a snap.

Additional Information:

• Standard Mercury Exhaust Hole Locations
• How To Measure For Custom Tailpipes

Cyclone Water Jacketed Header System For GM Big Block With Custom Dimension Tailpipes - Fully Polished

This Cyclone wet exhaust series header works perfectly on both stock and modified performance applications This header mixes engine cooling water with the exhaust near the end of the tailpipe That allows you to use a 4" rubber hose connection to attach your transom mounted exhaust tips This is the perfect replacement for your factory exhaust system. Oil filter bracket, shift control bracket, and ECU bracket not included. Gaskets and bolts are included.

If you are one of thousands of performance boaters seeking the power and styling from stainless steel tubular headers then you're looking at the leader in exhaust technology These "Cyclone" header systems share 100% 316L stainless steel construction. All appropriate flanges are laser cut and CNC machined for a perfect gasket seal. Each individual exhaust tube is bent to precise, exact tolerances every time. A computer designed fully welded water inlet manifold provides equal water distribution to each exhaust runner tube. While each set of headers goes through a 1900 degree annealing process that multiplies the durability factor of the header many times over while providing added protection against corrosion. But the heart of these systems lies in the ability to generate loads of additional power. By using CAD-5 Technology to develop a unique staggered tube runner length, these systems are capable of maximizing the broadest low end and midrange torque, all the while yielding incredible peak power gains. These systems are available in many configurations to fit every boaters needs. Rest assured when you lay down your hard earned money because the system comes complete with all necessary mounting bolts and gaskets making installation a snap.

Additional Information:

• Standard Mercury Exhaust Hole Locations
• How To Measure For Custom Tailpipes

Priced according to your dimensions.  Submit your custom measurements for a price quote.

Cyclone Sound-Select™ Header System For GM Big Block Bravo - Fully Polished

This is one of the easiest horsepower enhancing exhaustsystems available today! For boats currently using a switch-able exhaust diverter system, this was designed to replace MerCruiser® big block silent choice systems. This system will save up to 80 lbs compared to cast iron ones. Oil filter bracket, shift control bracket, and ECU brackets sold separately. Gaskets, and bolts are included.

If you are one of thousands of performance boaters seeking the power and styling from stainless steel tubular headers then you're looking at the leader in exhaust technology. These "Cyclone" header systems share 100% 316L stainless steel construction. All appropriate flanges are laser cut and CNC machined for a perfect gasket seal Each individual exhaust tube is bent to precise, exact tolerances every time. A computer designed fully welded water inlet manifold provides equal water distribution to each exhaust runner tube. While each set of headers goes through a 1900 degree annealing process that multiplies the durability factor of the header many times over while providing added protection against corrosion. But the heart of these systems lies in the ability to generate loads of additional power. By using CAD-5 Technology to develop a unique staggered tube runner length, these systems are capable of maximizing the broadest low end and midrange torque, all the while yielding incredible peak power gains. These systems are available in many configurations to fit every boaters needs. Rest assured when you lay down your hard earned money because the system comes complete with all necessary mounting bolts and gaskets making installation a snap.

Additional Information:

• Standard Mercury Exhaust Hole Locations

Cyclone Low Exit System Header System For GM Big Block Bravo - Fully Polished

This Hardin Marine Cyclone system is designed around an application where an incorporated swim platform creates the need to exit the exhaust in a lower than standard location Through the use of a floating elbow positioning of the exit is somewhat maneuverable, these systems are perfect for limited access applications. Oil filter bracket, shift control bracket, and ECU bracket not included. Gaskets and bolts are included.

If you are one of thousands of performance boaters seeking the power and styling from stainless steel tubular headers then you're looking at the leader in exhaust technology. These "Cyclone" header systems share 100% 316L stainless steel construction. All appropriate flanges are laser cut and CNC machined for a perfect gasket seal. Each individual exhaust tube is bent to precise, exact tolerances every time. A computer designed fully welded water inlet manifold provides equal water distribution to each exhaust runner tube. While each set of headers goes through a 1900 degree annealing process that multiplies the durability factor of the header many times over while providing added protection against corrosion. But the heart of these systems lies in the ability to generate loads of additional power. By using CAD-5 Technology to develop a unique staggered tube runner length, these systems are capable of maximizing the broadest low end and midrange torque, all the while yielding incredible peak power gains. These systems are available in many configurations to fit every boaters needs. Rest assured when you lay down your hard earned money because the system comes complete with all necessary mounting bolts and gaskets making installation a snap.

Additional Information:

• Standard Mercury Exhaust Hole Locations

Cyclone Water Jacketed Header System For GM Big Block Standard Dimension TRS - Fully Polished

This Cyclone wet exhaust series header works perfectly on both stock and modified performance applications This header mixes engine cooling water with the exhaust near the end of the tailpipe That allows you to use a 4" rubber hose connection to attach your transom mounted exhaust tips This is the perfect replacement for your factory exhaust system. Oil filter bracket, shift control bracket, and ECU bracket not included. Gaskets and bolts are included.

If you are one of thousands of performance boaters seeking the power and styling from stainless steel tubular headers then you're looking at the leader in exhaust technology These "Cyclone" header systems share 100% 316L stainless steel construction. All appropriate flanges are laser cut and CNC machined for a perfect gasket seal. Each individual exhaust tube is bent to precise, exact tolerances every time. A computer designed fully welded water inlet manifold provides equal water distribution to each exhaust runner tube. While each set of headers goes through a 1900 degree annealing process that multiplies the durability factor of the header many times over while providing added protection against corrosion. But the heart of these systems lies in the ability to generate loads of additional power. By using CAD-5 Technology to develop a unique staggered tube runner length, these systems are capable of maximizing the broadest low end and midrange torque, all the while yielding incredible peak power gains. These systems are available in many configurations to fit every boaters needs. Rest assured when you lay down your hard earned money because the system comes complete with all necessary mounting bolts and gaskets making installation a snap.

Additional Information:

• Standard Mercury Exhaust Hole Locations
• How To Measure For Custom Tailpipes

Cyclone H/P Air Sound-Select Header System For GM Big Block Bravo - Fully Polished

At last, a true high performance header with an air activated diverter built-in This gorgeous, one-piece-design tailpipe is the perfect choice for the power hungry boater who is seeking to reduce noise This system is sold complete with all necessary hose fittings, pump, gaskets, and bolts. Oil filter bracket, shift control bracket, and ECU bracket not included.

If you are one of thousands of performance boaters seeking the power and styling from stainless steel tubular headers then you're looking at the leader in exhaust technology.  These "Cyclone" header systems share 100% 316L stainless steel construction.  All appropriate flanges are laser cut and CNC machined for a perfect gasket seal Each individual exhaust tube is bent to precise, exact tolerances every time.  A computer designed fully welded water inlet manifold provides equal water distribution to each exhaust runner tube.  While each set of headers goes through a 1900 degree annealing process that multiplies the durability factor of the header many times over while providing added protection against corrosion.  But the heart of these systems lies in the ability to generate loads of additional power. By using CAD-5 Technology to develop a unique staggered tube runner length, these systems are capable of maximizing the broadest low end and midrange torque, all the while yielding incredible peak power gains.  These systems are available in many configurations to fit every boaters needs.  Rest assured when you lay down your hard earned money because the system comes complete with all necessary mounting bolts and gaskets making installation a snap.

Additional Information:

• Standard Mercury Exhaust Hole Locations

Cyclone "BIG GUN" System For GM Big Block - Fully Polished

At last the Biggest and the Best System available for the ultimate in performance These systems use an actual 4" internal pipe with a massive 4-1/2" outer shell These systems produce almost non-existent restriction to exhaust flow through the double wall water jacketed transom tail section These systems are referenced as dry tailpipe due to the fact exhaust flow never makes contact with the discharged water Each of these systems are designed for large cubic inch high horsepower and supercharged applications Additional transom sealing rings will need to be purchased separately When only the best will do Cyclone delivers Note: all Big Gun riser/tailpipes are custom built, a simple measurement guide is all that's needed to complete Allow 7-14 working days to build.

If you are one of thousands of performance boaters seeking the power and styling from stainless steel tubular headers then you're looking at the leader in exhaust technology. These "Cyclone" header systems share 100% 316L stainless steel construction. All appropriate flanges are laser cut and CNC machined for a perfect gasket seal. Each individual exhaust tube is bent to precise, exact tolerances every time. A computer designed fully welded water inlet manifold provides equal water distribution to each exhaust runner tube. While each set of headers goes through a 1900 degree annealing process that multiplies the durability factor of the header many times over while providing added protection against corrosion. But the heart of these systems lies in the ability to generate loads of additional power. By using CAD-5 Technology to develop a unique staggered tube runner length, these systems are capable of maximizing the broadest low end and mid range torque, all the while yielding incredible peak power gains. These systems are available in many configurations to fit every boaters needs. Rest assured when you lay down your hard earned money because the system comes complete with all necessary mounting bolts and gaskets making installation a snap.

Additional Information:

• Standard Mercury Exhaust Hole Locations
• How To Measure For Custom Tailpipes

Note:  Pricing indicated includes STANDARD DIMENSION Tailpipes only.  Custom Tailpipes may incur additional charges depending on the length and complexity of the tailpipe required.

Cyclone Dry System For GM Big Block Custom Dimension Dry System - Fully Polished

For those of you seeking the ultimate performance from your large cubic inch, aggressively cammed, naturally aspirated or supercharged engines This double-walled tailpipe discharges all of its cooling water through a 3/4" NPT bung in the side of the tailpipe It keeps the exhaust gas from coming in contact with any discharged water These tailpipes extend through the transom and require the additional purchase of transom sealing rings.

If you are one of thousands of performance boaters seeking the power and styling from stainless steel tubular headers then you're looking at the leader in exhaust technology These "Cyclone" header systems share 100% 316L stainless steel construction All appropriate flanges are laser cut and CNC machined for a perfect gasket seal. Each individual exhaust tube is bent to precise, exact tolerances every time. A computer designed fully welded water inlet manifold provides equal water distribution to each exhaust runner tube. While each set of headers goes through a 1900 degree annealing process that multiplies the durability factor of the header many times over while providing added protection against corrosion. But the heart of these systems lies in the ability to generate loads of additional power. By using CAD-5 Technology to develop a unique staggered tube runner length, these systems are capable of maximizing the broadest low end and midrange torque, all the while yielding incredible peak power gains. These systems are available in many configurations to fit every boaters needs. Rest assured when you lay down your hard earned money because the system comes complete with all necessary mounting bolts, gaskets, and shift and oil filter brackets making installation a snap.

Additional Information:

• Standard Mercury Exhaust Hole Locations
• How To Measure For Custom Tailpipes

Note:  Pricing indicated includes STANDARD DIMENSION Tailpipes only.  Custom Tailpipes may incur additional charges depending on the length and complexity of the tailpipe required.

Cyclone 4.50" "BIG GUN" Below Platform System For GM Big Block - Fully Polished

Description: For those high horsepower supercharged engine applications that require an exhaust exit that's basically 12" lower than a standard Bravo application. These systems feature a 4.-1/2" external pipe with a 4" internal pipe. These systems produce almost non-existent restriction to exhaust flow through the double wall water jacketed transom tail section. These systems are referenced as dry tailpipe due to the fact exhaust flow never makes contact with the discharged water. These systems are VERY LOUD due to unrestricted exhaust flow. Additional transom sealing rings will need to be purchased separately When only the best will do Cyclone delivers Note: all Big Gun riser/tailpipes are custom built, this price is based on the system referenced above. Changes or modifications could cost more. Fill out this simple measurement guide to get started. Allow 7-14 working days to build.