Sierra 18-1908 Manifold Riser Spacer 3 Inch

The Sierra 18-1908 Manifold Riser Spacer is a 3" riser extension designed for marine exhaust systems on MerCruiser stern drive engines. These Sierra extensions provide the extra height to prevent water from traveling back into the riser when throttling down and can also provide additional clearance for exhaust hose routing.

Key Features:

• Manufactured as a direct replacement and fully interchangeable with OEM products, primed and painted for added durability
• Machined mating surfaces that eliminate additional preparation to establish a proper seal
• Leak tested prior to paint to ensure quality
• Special casting techniques create uniform wall thickness
• Ready to install out-of-the-box

This riser spacer is compatible with GM based V6 carb and TBI engines with 2 piece exhaust manifolds. Use with Manifold 18-1952-1, Exhaust Elbow Mounting Kit 18-8554 and 18-8555, or Manifolds 18-1953-2 and 18-1957-1. Note: This is the spacer only; complete kit with mounting hardware and gaskets is available separately as part number 18-1908K.