Sierra 18-1957-2 MerCruiser 340 454 V8 Big Block Marine Exhaust Manifold 89011


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New exhaust manifold for MerCruiser 330, 340, and 454 Magnum Big Block V8 marine gas engines (GM/Chevrolet). This manifold is a center rise style, will fit either side of the engine, and accepts all original mounting brackets. Comes with gaskets and all necessary plugs. Each purchase is for one manifold.

This manifold is new and high-quality cast iron construction. For tips on replacing exhaust manifolds and risers, see my eBay guide. To determine if this is the correct replacement for you, look on your current manifold for casting numbers and match them to the cross-reference below:

Cross ReferencePart Number
MerCruiser807078A6, 89011A8, 89011
Osco Motors9011
Barr MarineMC-1-89011
Sierra Marine18-1957-1, 18-1957-2
Aqua Power5506
GLM Products51240
Marine Power0991-100

About Sierra
Sierra provides premium-quality aftermarket replacements for over 6,000 marine parts, tools, and components. Sierra products are engineered to meet or exceed OEM standards, and stand up in harsh marine environments. Every new Sierra part comes with a limited lifetime warranty that covers the useful life of the product against any defects in workmanship and materials.

Product Details

WarrantyLimited Lifetime
TypeExhaust Manifold
Shipping Dimensions21" x 10" x 7"
Part Number18-1957-2
Shipping Weight55 lbs
Country of ManufactureTaiwan
Manufacturer Part Number18-1957-2
Item Weight54.9 lbs