Seaward Series Exhaust Systems - Seaward Series Parts, Accessories and Tailpipes

Cast Stainless Fitting 3/4" NPT To 1" Straight - Short
Your Price:
$15.99

Cast Stainless Fitting 3/4" NPT To 1" Straight - Short

540-222132

Cast 316L Stainless Steel Fitting, Short
3/4" NPT To 1" Straight

We Offer the most complete line of chrome plated brass and custom fabricated stainless steel fittings available anywhere.  All of these fittings are sure to simplify your plumbing job and add a tasteful finishing touch. This is shorter than the normal 540-222110 fitting for a more compact installation. Used on Seaward manifolds.


Rubber Seal for Cable Thru Hull
Your Price:
$3.00

O-Ring for 620-32943 and 620-32947

625-1211

  • Replacement O-Ring for620-32943 and 620-32947
  • Two O-rings are needed for each fitting


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.


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 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.


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.


Replacement Seaward Series 8.1L / 496 Riser Install Kit
Your Price:
$59.99

Replacement Seaward Series 8.1L / 496 Riser Install Kit

620-38071

This kit contains the fittings and bolts to install a pair of risers on a 8.1L / 496 Mercrusier Seaward exhaust system.


Extreme Duty Hi-Performance Exhaust Manifold Gaskets - 454/502 Chevy
Your Price:
$29.99

Extreme Duty Hi-Performance Seaward / Cyclone Exhaust Manifold Gaskets - 454/502/525 Chevy

300-1413

Extreme Duty Hi-Performance Seaward / Cyclone Exhaust Manifold Gaskets - Stock Square Port 454/502/525 Chevy - Sold in Pairs

These gaskets are graphite impregnated and designed to withstand the highest of temperatures on high horsepower applications. Double drilled for both standard BBC and 525 applications. These gaskets are designed to be used with Hardin Marine's Seaward / Cyclone Exhaust Manifolds. Will work on other Big Block Chevy Manifolds as well. 

Sold in Pairs


Extreme Duty Hi-Performance D Port Exhaust Manifold Gaskets - 454/502/8.2L Chevy
Your Price:
$59.99

Extreme Duty Hi-Performance D Port Exhaust Manifold Gaskets - 454/502/8.2L Chevy

300-1417

Extreme Duty Hi-Performance D Port Exhaust Manifold Gaskets - 454/502/8.2L Chevy - Sold in Pairs - Replaces OEM Mercury #27-8M0065690

These gaskets are graphite impregnated and designed to withstand the highest of temperatures on high horsepower applications. For those of you looking to do the job only once, insist on Hardin Marine Extreme Duty gaskets. Quite possibly the last gasket you'll ever need. These gaskets are designed to be used in D port Exhaust applications. Replaces stock OEM Mercury #27-8M0065690

Sold in Pairs


Seaward Series Replacement Riser Gasket
Your Price:
$11.99

Seaward Series Replacement Riser Gasket

620-38006

Replacement riser gasket for Hardin Seaward manifolds and risers. 4-1/2" x 3" Bolt pattern.


Seaward Turbulator
Your Price:
$37.99

Seaward Turbulator

620-38089

Seaward Turbulator

Designed for seaward series exhaust systems.

Turbulators are designed to keep any condensation or moisture from entering the manifold during the cool down process This is one of the many unique Hardin features that are helping lead the way in exhaust system technologies. Sold each, gaskets sold separately. 2 gaskets are needed per 1 turbulator.

Shift Bracket for CMI Gen-X and Hardin Hurricane, Seaward 525 / 700 Exhaust
Your Price:
$129.99

Shift Bracket for CMI Gen-X and Hardin Hurricane, Seaward 525 / 700 Exhaust

650-28235P

Shift Bracket for CMI Gen-X and Hardin Hurricane, Seaward 525 / 700 Exhaust

This is a bracket only for installing yourself on compatible headers.


Seaward Series Shift Quadrant / EFI Bracket
Your Price:
$59.99

Seaward Series Shift Quadrant / EFI Bracket

620-38051

This Shift / EFI bracket fits Hardin Marine Seaward Series Exhaust Systems. Can be used for either application.

NOTE: If using with a riser mounted O2 Sensor, modification to bracket will be required or O2 sensor moved inboard.


Seaward Series Oil Filter Bracket
Your Price:
$109.99

Seaward Series Oil Filter Bracket

620-38050

This oil filter bracket fits Hardin Marine Seaward Series Exhaust Systems.

Seaward O2 Oxygen Sensor Adapter Flange
Your Price:
$99.99

Seaward O2 Oxygen Sensor Adapter Flange

620-38080

Whether you're a tuner seeking to add a popular Air/Fuel ratio gauge or you're entering the world of aftermarket fuel injection we have developed the critical part to make this addition a snap. This billet aluminum anodized wedge is at just the perfect angle to allow re-connection of your original exhaust hose. The kit includes (1) O2 adapter wedge, (2) gaskets, and (2) new front attachment studs. Bolt pattern is 3" x 4.5". Designed to fit the Hardin Marine Seaward Manifolds only.


Seaward O2 Wedge / Gauge Kit

Your Price:
$409.99

Seaward O2 Wedge / Gauge Kit

620-38081 + Option(s)

Seaward O2 Wedge / Gauge Kit

  • Gauge kit includes custom tuned .1 AFR Resolution Bosch LSU 4.9 Sensor, 8ft. wiring harness, 304 stainless steel weld-in bung, mounting hardware, and detailed instructions for installation
  • 0-5v data and serial data outputs for ECU, data acquisition unit, or Laptop tuning
  • User programmable range for Rich/Stoic/Lean conditions
  • Peak recall/memory
  • 10:1 to 20:1 AFR range for gasoline applications
  • 12 and 16 volt compatible, compatible with nearly every street car or race car electrical system
  • User Programmable Warning Function
  • Display data in Lambda or numerical A/F ratio

Whether you're a tuner seeking to add a popular Air/Fuel ratio gauge or you're entering the world of aftermarket fuel injection we have developed the critical part to make this addition a snap. This billet aluminum anodized wedge is at just the perfect angle to allow re-connection of your original exhaust hose. The kit includes (1) O2 adapter wedge, (1) gasket, and (2) new front attachment studs.


Stainless Steel 18MM Oxygen Sensor Plug
Your Price:
$23.95

Stainless Steel 18MM Oxygen Sensor Plug

620-50031

Stainless Steel 18MM Oxygen Sensor Plug

This plug only is designed fit popular O2 bungs and ports designed to allow you to cap/plug a oxygen sensor bung  Price does not include bung only plug. Sold Each. 18mm x 1.5

Note: This is a plug only

Stainless Steel 18MM Oxygen Sensor Plug - Hex Head
Your Price:
$23.95

Stainless Steel 18MM Oxygen Sensor Plug - Hex Head

620-50033

Stainless Steel 18MM Oxygen Sensor Plug - Hex Head

This plug only is designed fit popular O2 bungs and ports designed to allow you to cap/plug a oxygen sensor bung  Price does not include bung only plug. Sold Each. 18mm x 1.5, Hex Head.

Note: This is a plug only

Stainless Steel Lifetime Series Sea Pump Drain Plugs - Mercruiser 22-806608A02 / 8M2000874
Your Price:
$5.59

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

Stainless Steel Lifetime Series Sea Pump Drain Plugs - Mercruiser 22-806608A02 / 8M2000874

625-4289

***WARNING**** Do not fall victim to the failure of the OEM blue plastic drain plugs. The factory cheap plugs crack, break off and create service to nightmares to actual water leaks into your boat. Hardin Marine has designed the "Lifetime Series" drain plugs to perfectly blend with their award winning lifetime series sea pumps. Whether your replacing your sea pump or merely servicing your boat you cannot afford to not update to the simple to install safer drain plugs. these replacements for Mercruiser #22-806608A02 / 8M2000874 from Hardin Marine are polished Stainless Steel and will last a lifetime!

The thread on this plug is 1/2-13

Open Sealing Tube for LS Exhaust Manifolds
Your Price:
$23.99

Open Sealing Tube for LS Exhaust Manifolds

620-32943

Open Sealing Tube for LS Exhaust Manifolds.