My Account
Shopping Cart

Sierra 18-1902 Starboard Exhaust Manifold for OMC GM V8 Small Block

Manufacturer

Sierra

<h3>Sierra: Six Decades of Marine Aftermarket Excellence</h3><p><strong>Sierra</strong> has spent nearly 60 years earning its reputation as one of the most trusted names in the marine aftermarket industry. Originally focused on engine and drive components for boats, the brand has grown into a comprehensive source for nearly everything a boater needs to keep their vessel running at its best — from precision instrumentation to complete engine rebuild hardware.</p><p>Now operating as a brand of Dometic, Sierra manages global aftermarket distribution from a 300,000 sq. ft. facility in Litchfield, Illinois. The Sierra brand today encompasses not only its flagship marine parts line but also well-established marine names like Shields and Moeller, offering boaters a broader catalog than ever before. Whether you own an outboard, inboard, or sterndrive, Sierra's engineering team designs products to meet or exceed OEM specifications.</p><h3>Precision Instrumentation You Can Trust on the Water</h3><p>One of Sierra's most recognized product areas is its marine instrumentation lineup. The brand's <a href="/7570-sierra-gauge-set-1480">gauge sets</a> cover everything from classic analog instrument clusters to advanced digital multi-function displays. Sierra offers packages suited to outboards, sterndrives, and gasoline-powered inboards, with options ranging from coordinated analog kits in styles like Arctic, Eclipse, and Amega to modern touchscreen solutions like the R3 multi-function gauge. Features such as scratch-resistant domed glass lenses, silicone-dampened pointers, and perimeter backlighting make these instruments highly readable in all conditions.</p><p>Behind every accurate gauge reading is a properly calibrated sending circuit. Sierra's <a href="/7570-sierra-gauge-resistor-47908">gauge resistors</a> are a critical part of that chain, ensuring the signals from sensors and sending units are correctly interpreted by your instruments. These components are built to marine-grade standards to resist moisture, vibration, and corrosion — the realities of life on the water.</p><h3>Engine Internals Built to OEM Standards</h3><p>Sierra's history in marine power is perhaps best demonstrated by its deep catalog of engine components. The brand's <a href="/7570-sierra-engine-gasket-set-5404">engine gasket sets</a> cover a wide range of outboard and inboard applications and are engineered to deliver reliable seals in the demanding thermal and chemical environment of a marine engine. For boaters performing seasonal overhauls, top-end rebuilds, or full engine restorations, Sierra gasket kits are a go-to resource trusted by professional marine technicians and DIY boaters alike.</p><h3>A Complete Marine Parts Partner</h3><p>Beyond instrumentation and engine internals, Sierra's catalog spans fuel systems, electrical supplies, steering components, shore power, and more — all covered by what the brand calls an industry-leading warranty. Sierra also maintains a comprehensive parts-finder tool that enables cross-referencing with OEM part numbers from major manufacturers including Mercury, Yamaha, Suzuki, Volvo Penta, and others, making it straightforward to find the right replacement part for virtually any application.</p>

Part Number

18-1902
09/12/2036 4:35 AM
Sale Price

$360.03

In Stock (8)

delivery box

Usually delivered within 2 days

free shipping

FREE SHIPPING

Authorize Seller Badge
No Hassle Returns

No Hassle Returns

Live-in-stock inventory

Live-in-stock inventory

Fitment guaranteed

Fitment guaranteed

Product Details

The Sierra 18-1902 is a high-quality starboard side exhaust manifold designed specifically for OMC Cobra stern drive applications with GM small block V8 engines. This heavy-duty cast iron manifold fits 5.0L and 5.7L (305 and 350 cubic inch) marine engines equipped with end riser style exhaust systems, commonly found in 1987-1989 OMC models.

Key Features:

  • Heavy-duty cast iron construction for maximum durability and heat resistance
  • Factory painted black finish for corrosion protection
  • Professionally leak tested before packaging to ensure quality
  • Includes exhaust manifold gaskets and drain cap with hose clamp
  • Precision-cast with smooth mating surfaces for proper sealing
  • Designed to meet or exceed OEM specifications

Replacement Information:

  • Replaces OEM part numbers: OMC 912441, 909280
  • Cross-references: GLM 51410, Barr OMC-1-912441, Mallory 9-40602, Osco 2441
  • Recommended mounting kit: Sierra 18-8502 (sold separately)
  • Compatible exhaust elbow: Sierra 18-1921

Sierra marine engine parts are manufactured to stringent quality standards, providing reliable performance for demanding marine environments. This starboard manifold is engineered for proper fitment on GM small block V8 applications with log-style end rise manifold configurations.

Products specifications

Application

V8 Starboard Side - most GM V8 small blocks with end riser. Uses mounting kit 8502

Replaces

OMC Sterndrive/Cobra 912441

Awesome love the site

No problems everything was perfect .

Very user friendly.

Don't know. Nothing has happened yet.

It was what my grandson needed to fix up his old Jeep he's been working on.

Very satisfied and very competitive price.

good and quick

Fast shipping and best price on the web! I will be back and will recommend the site to friends.

The only thing I would like to know is what the manifold kit comes with for hardware. Its not specified if they come with any hardware or gaskets at all and i would like to be prepared to do the job when they arrive in the mail.

All seems great. Had item in stock as on there website and it was shipped quickly.

Price was very cheap. The cheapest I could find anywhere. Should be at my house soon. Very easy cite to navigate.

Your online catalog was simple to navigate and you have competitively low prices on top of a variety of economy to name brand quality parts. Your website was the only place that carried the specific brand oil pump i was searching for and the great pricing

Anxious to try your product

Had to do order twice. Hope I don't get charged twice.

Could not find the part I was looking for at any other 4x4 website. Found it here and it was cheaper than almost every other place. Since I saved some I went ahead and paid the extra for 2-day shipping and still came out on top price wise. Definitely will be checking here again for parts for my Jeep!

I am so pleased I found autoplicity online. Prices cannot be beaten anywhere on a extend a truck item. Quick shipping. I placed the site in my favorites and telling friends about it. Thank you guys for a great product.

Share icon
Return Policy
Returns are easy at Boatplicity

Not happy with a purchase? No problem. We've made returning items as easy as possible. And most purchases can be returned for free for 30 days. Learn more about our Returns Policy