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Seaward Series Exhaust Systems - Seaward Series Small Block Chevy 305 / 350 Exhaust Systems

Replacement Seaward Series Small Block Chevy Manifold Install Kit
Your Price:
$59.99

Replacement Seaward Series Small Block Chevy Manifold Install Kit

620-38031

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


Seaward Series Replacement Small Block Chevy Manifolds
Starting From:
$1,599.99

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

Seaward Series Replacement Small 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 "Alpha/Bravo" Small Block Chevrolet Exhaust System

Starting From:
$1,999.99

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

Seaward Series "Alpha/Bravo" Small Block Chevrolet Exhaust System

620-38045 + 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 350HP 
  • 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
  • Risers include O2 Sensor bungs and plugs.
  • Kit includes all bolts and gaskets needed for installation

Seaward Series "Alpha/Bravo - 3" Taller" Small Block Chevrolet Exhaust System

Starting From:
$2,499.99

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

Seaward Series "Alpha/Bravo - 3" Taller" Small Block Chevrolet Exhaust System

620-38044 + 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 350HP 
  • 3" Taller 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 "Alpha/Bravo - 6" Taller" Small Block Chevrolet Exhaust System

Starting From:
$3,499.99

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

Seaward Series "Alpha/Bravo - 6" Taller" Small Block Chevrolet Exhaust System

620-38109 + 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 350HP 
  • 6" Taller 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 SBC Dry Joint Exhaust System

Starting From:
$2,799.99

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

Seaward Series SBC Dry Joint Exhaust System

620-3813 + Option(s)

  • DO YOU HAVE DRY JOINT EXHAUST? CLICK HERE TO LEARN MORE.
  • Mercruiser Dry Joint Replacement
  • Replaces 14 degree, Dry Joint "Tall" Riser systems, "Short" 7 degree systems will require custom tailpipes
  • The term Mercruiser Dry Joint Exhaust refers to a later model (2002 and newer) OEM exhaust system which utilizes 2 coolant passages vs 4, between the manifold and riser that are separated outside of the exhaust gasket. 
  • 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 400HP 
  • 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
  • Risers include O2 Sensor bungs and plugs.
  • MerCruiser changed their exhaust system design in 2002 by creating a Dry-Joint exhaust system thus removing the cooling water passages from the perimeter of the riser and manifold flange area.  Dry-Joint is a proven enhanced design exhaust manifold and exhaust riser compared to standard “Wet-Gasket” style of marine exhaust manifolds and exhaust risers common to early or old style marine industry offerings

Seaward Series "Alpha/Bravo XL" Small Block Chevrolet Exhaust System

Starting From:
$2,799.99

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

Seaward Series "Alpha/Bravo XL" Small Block Chevrolet Exhaust System

620-38048 + 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 400HP 
  • 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 "Alpha/Bravo HP Magnum" Small Block Chevrolet Exhaust System

Starting From:
$3,499.99

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

Seaward Series "Alpha/Bravo HP Magnum" Small Block Chevrolet Exhaust System

620-38049 + 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 450HP 
  • Magnum HP 500 Style 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 Low Port Small Block Chevrolet Exhaust System

Starting From:
$3,399.99

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

Seaward Series Low Port Small Block Chevrolet Exhaust System

620-38106 + 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 350HP 
  • Low Port 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 "Low Exit" Small Block Chevrolet Exhaust System

Starting From:
$2,299.99

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

Seaward Series "Low Exit" Small Block Chevrolet Exhaust System

620-38182 + 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 jet boat applications or boats with a crank centerline style exhaust exit to 400HP 
  • 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 "Ski Boat" Small Block Chevrolet Exhaust System

Starting From:
$3,599.99

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

Seaward Series "Ski Boat" Small Block Chevrolet Exhaust System

620-38116 + 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 400HP 
  • 3.5" Outlet Riser for performance ski boat applications
  • Polished Stainless steel tailpipe is manufactured from premium 316L Stainless steel, 4" OD  (3.5" outlet)
  • 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 6.2L, 350 Mag MPI, 350 MPI Alpha-Bravo EC  (Catalyzed-Delete) Exhaust System

Starting From:
$3,899.99

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

Seaward Series 6.2L, 350 Mag MPI, 350 MPI Alpha-Bravo EC (Catalyzed-Delete) Exhaust System

620-38123 + Option(s)

  • Eliminate Catalyzed Exhaust Systems
  • 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 400HP 
  • 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
  • Requires Catalyst Eliminator Computer (See Related Parts)
  • We need to know your current riser height to make sure the risers will fit. See this image, we need height labeled "C". or find the part number on the riser such as in this image.

NOTE: THIS SYSTEM REQUIRES A HIGH DEGREE OF TECHNICAL APTITUDE TO INSTALL AND CONFIGURE. YOU MUST CALL AND SPEAK WITH OUR TECH SUPPORT DEPARTMENT BEFORE GETTING A QUOTE.

WARNING! This system is not to be used on emissions regulated waterways. The intent of this system is to allow the running of a catalyzed marine engine without the catalytic converters installed and without triggering any ECU error codes. With the engine operating in this condition, the emissions control system will be rendered inoperative. For this reason, do not operate the vessel on emissions regulated waterways. This system is not legal for any purpose other than testing purposes and not for use on any state or federal waterway.


Seaward Series 6.2L, 350 Mag MPI, 350 MPI Alpha-Bravo EC  (Catalyzed-Delete) 2" Taller Exhaust System

Starting From:
$4,999.99

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

Seaward Series 6.2L, 350 Mag MPI, 350 MPI Alpha-Bravo EC (Catalyzed-Delete) 2" Taller Exhaust System

620-38208 + Option(s)

  • Eliminate Catalyzed Exhaust Systems
  • 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 400HP 
  • 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
  • Requires Catalyst Eliminator Computer (See Related Parts)
  • 2" Taller Than Stock Risers
  • We need to know your current riser height to make sure the risers will fit. See this image, we need height labeled "C". or find the part number on the riser such as in this image.

NOTE: THIS SYSTEM REQUIRES A HIGH DEGREE OF TECHNICAL APTITUDE TO INSTALL AND CONFIGURE. YOU MUST CALL AND SPEAK WITH OUR TECH SUPPORT DEPARTMENT BEFORE GETTING A QUOTE.

WARNING! This system is not to be used on emissions regulated waterways. The intent of this system is to allow the running of a catalyzed marine engine without the catalytic converters installed and without triggering any ECU error codes. With the engine operating in this condition, the emissions control system will be rendered inoperative. For this reason, do not operate the vessel on emissions regulated waterways. This system is not legal for any purpose other than testing purposes and not for use on any state or federal waterway.


Seaward Series "Dry Pipe" Small Block Chevrolet Exhaust System

Starting From:
$2,999.99

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

Seaward Series "Dry Pipe" Small Block Chevrolet Exhaust System

620-38114 + 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 500+ HP 
  • 4" Dry 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

Replacement Seaward Series Small Block Chevy Riser Install Kit
Your Price:
$64.99

Replacement Seaward Series Small Block Chevy Riser Install Kit

620-38046

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


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