Seaward Series Big Block Chevy Exhaust System

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

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

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 manufactures 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.

The Seaward Bravo "HP" system is designed for use on factory high performance elbow top engine applications which use a CMI tailpipe. The raised or arched tailpipe provides accelerated water exit and is key to providing increased reversion resistance. The stainless steel tailpipe is manufactured from premium 316l Stainless steel not 304/303 low grade SS many competitors use. Also these tailpipes feature a 4" O.D and a 3-1/2" I.D. for maximum exhaust flow. These systems are perfect for engines rated up to 525HP.

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: The optional "Ocean Series", 1000 hour salt spray coating provides extreme corrosion treatment. 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: 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.

Fits: Applications which use CMI Elbow Top Tailpipe, Mercury HP500 EFI Applications.

NOTE: Modified engines using larger than stock, aftermarket camshafts may require a modified "Dry Exhaust Stream" tailpipe system to prevent reversion. Call us to consult what your needs might require if you are uncertain. Our XL and HP systems WILL NOT work with exhaust diverter systems. or S-Pipes

(If you are replacing an existing exhaust system, please note our systems are designed to exit in stock Mercruiser Bravo exit hole/tip locations. See the guide here. It is the purchasers responsibility to confirm the dimensions for the correct fit prior to ordering!

The big-block Chevrolet has a firing order of 1-8-4-3-6-5-7-2. This means that In each exhaust manifold, we will have two cylinders that will fire In succession. Cylinders 8 & 4 on the starboard side manifold and cylinders 5 & 7 on the port side manifold. In the images of the competitor exhausts below, we can see the manifold has a divider that separates the exhaust pulses from cylinders 8 & 4. This divider keeps the exhaust gases of the number 4 cylinder from entering the number 8 cylinder when the number 8 exhaust valve Is still open. The port manifold actually groups cylinders 5 & 7 together. Without a divider between these two cylinders, the exhaust gases from the number 7 cylinder will enter the number 5 cylinder when the number 5 exhaust valve Is still open. This Is not what we want. Using this style manifold on both sides of a V8 engine Is not very efficient. As shown on the Seaward manifold however, all ports are truly separated, leading to better exhaust performance.

Optional Brackets
Shift Bracket (620-38051) [Add $59.99]
EFI Bracket (620-38051) [Add $59.99]
Oil Filter Bracket (620-38050) [Add $79.99]
Corrosion Protection Options
Ocean Series - Extreme Corrosion Protection Treament [Add $200.00]

All Seaward manifolds come powdercoated for corrosion protection standard. With this option, an additional hydrogen infused zinc process is applied to each manifold for over 1000 hours of durability.

Base Price: $2,999.99 Customized Price: $2,999.99
Stainless Steel Oxygen Sensor O2 Bung

Stainless Steel Oxygen Sensor O2 Bung Installed