Sierra Mercruiser Exhaust Manifold w/Hardware 18-1956-3

The Sierra 18-1956-3 is an exhaust manifold with hardware, built for Mercruiser exhaust systems. It is designed to work as part of a complete exhaust manifold assembly, pairing with the correct elbow, riser, gaskets, and mounting hardware to route exhaust gases away from the engine safely and reliably. This manifold is engineered to fit directly with Sierra's 18-1978 manifold elbow and 18-1975-1 manifold riser, both of which are listed by the manufacturer as compatible with this manifold. When installed with the 18-1978 elbow, the assembly uses the 18-2833 elbow gasket and 18-4362 mounting kit; when installed with the 18-1975-1 riser, the assembly uses the 18-2819-1 elbow gasket, 18-8551 mounting hardware, and 18-2748 exhaust boot. This gives installers a clear, documented path to building out a matched exhaust manifold system rather than guessing at compatible parts. At 47 pounds, this is a heavy-duty, full-size manifold intended for direct replacement in Mercruiser exhaust manifold applications. Sourcing a manifold with the correct manufacturer-specified mating parts helps ensure a proper seal and secure mounting, reducing the risk of exhaust leaks or improper fitment that can occur when parts are mixed from unverified sources.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-1956-3
• Category: Mercruiser Exhaust Manifolds
• Weight: 47 pounds
• UPC: 808282371463
• Compatible Manifold Elbow: 18-1978
• Compatible Manifold Riser: 18-1975-1
• Elbow Gasket (with 18-1978): 18-2833
• Mounting Kit (with 18-1978 elbow): 18-4362
• Elbow Gasket (with 18-1975-1 riser): 18-2819-1
• Mounting Hardware (with 18-1975-1 riser): 18-8551
• Exhaust Boot (with 18-1975-1 riser): 18-2748

Frequently Asked Questions

What is Sierra part 18-1956-3? It is a Sierra exhaust manifold with hardware, listed under Mercruiser exhaust manifolds, part number 18-1956-3.

Does the 18-1956-3 manifold come with mounting hardware? Yes, the 18-1956-3 is sold as an exhaust manifold with hardware included.

How much does the 18-1956-3 exhaust manifold weigh? The Sierra 18-1956-3 exhaust manifold weighs 47 pounds.

Which elbow fits the 18-1956-3 manifold? Sierra's 18-1978 manifold elbow is listed as compatible for use with the 18-1956-3 manifold.

Which riser fits the 18-1956-3 manifold? Sierra's 18-1975-1 manifold riser is listed as compatible for use with the 18-1956-3 manifold.

What gasket do I need if I install the 18-1978 elbow with this manifold? Use the 18-2833 elbow gasket when pairing the 18-1978 elbow with the 18-1956-3 manifold; it is included in the 18-4362 mounting kit.

What gasket do I need if I install the 18-1975-1 riser with this manifold? Use the 18-2819-1 elbow gasket when pairing the 18-1975-1 riser with the 18-1956-3 manifold.

What mounting hardware is used with the 18-1975-1 riser on this manifold? The 18-8551 hardware kit provides the mounting hardware for the 18-1975-1 riser used with the 18-1956-3 manifold, and the 18-2748 exhaust boot is used with that same riser.

What is included in the 18-4362 mounting kit? The 18-4362 mounting kit, used with the 18-1978 elbow on the 18-1956-3 manifold assembly, includes the 18-2833 elbow gasket.

Is the UPC for the 18-1956-3 exhaust manifold available? Yes, the Sierra 18-1956-3 exhaust manifold carries UPC 808282371463.

What category does the 18-1956-3 fall under? The 18-1956-3 is categorized as a Mercruiser exhaust manifold by Sierra.

Do I need to buy the elbow and riser separately from the 18-1956-3 manifold? Yes, the 18-1956-3 is the manifold itself; the 18-1978 elbow or 18-1975-1 riser, along with their respective gaskets and mounting hardware, are separate parts documented as compatible with this manifold.