Sierra Exhaust Manifold 18-1952-1, Replaces Mercruiser 99746A8, Fits MCM GM V-6 229 and 262 cid Engines 1985-2002

The Sierra 18-1952-1 is a direct-replacement exhaust manifold built for MCM GM V-6 229 and 262 cid engines (1985-2002). It is designed to fit either the port or starboard side of the engine, so a single part number covers both mounting positions. The manifold carries a machined exterior finish for a precise, reliable fit against the cylinder head and riser/elbow assembly, and it is supplied with a mounting package to simplify installation.

This manifold cross-references directly to Mercruiser 99746A8, 99746A17, and 99746A3, along with equivalent aftermarket numbers, making it a straightforward swap when replacing a worn, cracked, or corroded factory manifold. Sierra manufactures this part to meet or exceed the specifications of the original equipment it replaces, giving boat owners a dependable option for keeping their exhaust system sealed and functioning correctly. At 34 pounds, it matches the weight profile of the OEM cast manifold it is designed to replace.

Because the manifold connects directly to the exhaust riser and elbow, it is commonly serviced alongside related components such as manifold gaskets, riser elbows, and mounting kits. Always confirm your engine's exact model and cid rating before ordering to ensure correct fitment.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-1952-1
• Weight: 34 pounds
• Exterior Finish: Machined
• Mounting Position: Port and starboard
• Engine Fitment: MCM GM V-6 229 and 262 cid engines (1985-2002)
• Mounting Hardware: Supplied with mounting package
• UPC: 808282237448
• Category: Mercruiser Exhaust Manifolds

Fitment

• MCM GM V-6 229 and 262 cid engines (1985-2002)
• Fits port and starboard mounting positions

Replaces (OEM)

• Mercruiser 99746A8
• Mercruiser 99746A17
• Mercruiser 99746A3
• Barr MC-1-99746
• GLM 51220
• Mallory 9-40505
• Osco 9745

Frequently Asked Questions

What engines does the Sierra 18-1952-1 exhaust manifold fit? The 18-1952-1 fits MCM GM V-6 229 and 262 cid engines built between 1985 and 2002.

Does the 18-1952-1 fit both the port and starboard side? Yes, this manifold is designed to fit either the port or starboard mounting position, so one part number covers both sides.

What OEM Mercruiser part numbers does this manifold replace? The Sierra 18-1952-1 replaces Mercruiser 99746A8, 99746A17, and 99746A3.

Are there other aftermarket cross-reference numbers for this part? Yes, the 18-1952-1 also cross-references to Barr MC-1-99746, GLM 51220, Mallory 9-40505, and Osco 9745.

How much does the 18-1952-1 exhaust manifold weigh? It weighs 34 pounds.

What finish does the Sierra 18-1952-1 manifold have? It has a machined exterior finish for a precise fit against the cylinder head and riser assembly.

Does the 18-1952-1 come with mounting hardware? Yes, the Sierra 18-1952-1 is supplied with a mounting package for installation.

Is the Sierra 18-1952-1 a genuine Mercruiser part or an aftermarket equivalent? The 18-1952-1 is a Sierra-manufactured aftermarket manifold built to meet or exceed the specifications of the OEM Mercruiser 99746A8 and 99746A17 manifolds it replaces.

Will the 18-1952-1 work with my riser and elbow assembly? The 18-1952-1 manifold is compatible with standard riser elbow and gasket components used on MCM GM V-6 229 and 262 cid engine setups; confirm your specific riser and elbow part numbers before ordering.

What is the difference between the 18-1952-1 and a used OEM manifold? The 18-1952-1 is a new manifold manufactured to meet or exceed OEM specifications, offering consistent fit and finish compared to a used factory manifold that may show wear or corrosion.

Do I need to order a separate manifold for each side of the engine? No, because the 18-1952-1 fits either the port or starboard side, the same part number can be used on both sides of a V-6 engine that requires this manifold.

Does the 18-1952-1 include the manifold gasket? The listing for 18-1952-1 confirms it ships with a mounting package; gaskets specific to your riser and elbow combination should be selected separately based on that hardware.