Sierra 18-1908 3 Inch Manifold Riser Spacer for MerCruiser Marine Engines

The Sierra 18-1908 is a 3-inch manifold riser spacer designed for MerCruiser GM V6 and V8 marine engines with 2-piece exhaust manifolds. This critical exhaust system component provides additional height to prevent water from traveling back into the riser when throttling down, while also offering added clearance for exhaust hose routing.

Key Features:

• 3-inch spacer height for optimal exhaust system performance
• Primed and painted finish for added durability and corrosion protection
• Machined mating surfaces ensure proper seal without additional preparation
• Leak tested prior to painting to ensure quality construction
• Direct OEM replacement, fully interchangeable with original parts
• Ready to install right out of the box

Applications:

• MerCruiser GM V6 229 and 262 cu.in. (Models 185 and 205)
• GM Small Block V8 305-350 cu.in. (Models 200, 228, 230, 260, and 898)
• GM Big Block V8 454 cu.in. (Models 330, 340, and 7.4L)

Replaces OEM Numbers: MerCruiser 93320, 93322, 93320A2, 93320A3, 93320A5, 93320A6, 807476A6, 93320A13; GLM 50310; Barr MC-20-93320A3

Use With: Manifolds 18-1952-1, 18-1953-2, or 18-1957-1; Exhaust Elbows 18-1970-1, 18-1976-1; Exhaust Elbow Mounting Kits 18-8554, 18-8555, 18-8556; Gaskets 18-0672, 18-0897, 18-2849-1

This spacer is sold individually and is engineered to meet or exceed manufacturer specifications. For a complete installation kit with mounting hardware, gaskets, and plugs for both port and starboard sides, see Sierra 18-1908K.