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Seaward Series Exhaust Systems - Seaward Systems for Big Block Chevy 454 / 502

Seaward Series Replacement Big Block Chevy Manifolds
Starting From:
$1,799.99

This Part has options, please click the button below to order.

Seaward Series Replacement Big Block Chevy Manifolds

620-38 + Option(s)

  • 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!

Seaward Series Big Block Chevy Exhaust System

Starting From:
$2,399.99

This Part has options, please click the button below to order.

Seaward Series "Bravo" Big Block Chevrolet Exhaust System

620-38035 + Option(s)

  • 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

Seaward Series Big Block Chevy Exhaust System

Starting From:
$2,799.99

This Part has options, please click the button below to order.

Seaward Series "Bravo - 3" Taller" Big Block Chevrolet Exhaust System

620-38037 + Option(s)

  • 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

Seaward Series Big Block Chevy Exhaust System

Starting From:
$2,999.99

This Part has options, please click the button below to order.

Seaward Series "Bravo - 6" Taller" Big Block Chevrolet Exhaust System

620-38108 + Option(s)

  • 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

Seaward Series Big Block Chevy Exhaust System

Starting From:
$2,699.99

This Part has options, please click the button below to order.

Seaward Series "Bravo XL" Big Block Chevrolet Exhaust System

620-38038 + Option(s)

  • 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

Seaward Series Big Block Chevy Exhaust System

Starting From:
$3,699.99

This Part has options, please click the button below to order.

Seaward "Bravo HP" Series Big Block Chevrolet Exhaust System

620-38039 + Option(s)

  • 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

Seaward Series Big Block Chevy Exhaust System

Starting From:
$2,399.99

This Part has options, please click the button below to order.

Seaward Series "Low Exit" Big Block Chevrolet Exhaust System

620-38181 + Option(s)

  • 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

Seaward Series Big Block Chevy Exhaust System

Starting From:
$3,599.99

This Part has options, please click the button below to order.

Seaward Series "Low Port" Big Block Chevrolet Exhaust System

620-38105 + Option(s)

  • 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

Seaward Series Big Block Chevy Exhaust System

Starting From:
$3,899.99

This Part has options, please click the button below to order.

Seaward Series "Dry Tailpipe" For Stock Bravo Exit Location Big Block Chevy Exhaust System

620-38112 + Option(s)

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.


Seaward Series Big Block Chevy Exhaust System

Starting From:
$3,299.99

This Part has options, please click the button below to order.

Seaward "500 EFI / CMI Elbow Top Replacement" Series Big Block Chevrolet Exhaust System

620-38120 + Option(s)

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

Seaward Series Big Block Chevy Exhaust System

Starting From:
$3,899.99

This Part has options, please click the button below to order.

Seaward Mercruiser 8.1 / 496MAG and 496MAG HO Replacement Exhaust System

620-3806 + Option(s)

  • Manifold is powder-coated for corrosion protection
  • "Ocean Series" Extreme Corrosion Treatment available for additional interior corrosion protection is standard for 496 system.
  • Designed for use as replacement for OEM Mercruiser 496 manifolds and risers 
  • 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 brackets, bolts and gaskets needed for installation
  • 2", 6", and 8" taller versions have 2-3 week lead time for custom tailpipe construction.
  • Check your riser height to make sure you get the correct system.

Replacement Seaward Series Big Block Chevy Manifold Install Kit
Your Price:
$69.99

Replacement Seaward Series Big Block Chevy Manifold Install Kit

620-38032

This kit contains the fittings and bolts to install a pair of manifolds on a big block Chevy Seaward exhaust system.


Replacement Seaward Series Big Block Chevy Riser Install Kit
Your Price:
$69.99

Replacement Seaward Series Big Block Chevy Riser Install Kit

620-38036

This kit contains the gaskets, hoses and bolts to install a pair of risers on a big block Chevy Seaward exhaust system.


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