Sierra 18-8505 Exhaust Elbow Mounting Kit for 18-1976-2 Riser - GM V-6/V-8 229-454 CID Engines

The Sierra 18-8505 Exhaust Elbow Mounting Kit supplies the hardware and gasket needed to mount Sierra's 18-1976-2 Manifold Elbow (4 inch hose, 7 degree down angle) to the exhaust manifold on GM-based sterndrive and inboard engines. Rather than a single loose bolt or gasket, the kit bundles the mounting bolt and a 18-0897 elbow gasket together so the elbow-to-manifold connection can be resealed and reinstalled as a complete assembly, which is the typical failure point when an exhaust elbow starts weeping water or exhaust at the manifold joint.

This kit is built for GM Big Block V-8 454 cubic inch engines (Models 330, 340 and 7.4L), GM Small Block V-8 305-350 cubic inch engines (Models 200, 228, 230, 260 and 898), and Mercruiser GM V-6 229 and 262 cubic inch engines (Models 185 and 205). It is designed to work specifically with the 18-1976-2 riser/elbow, so confirm that part number is the elbow already installed on the engine before ordering. The kit is interchangeable with Mallory 9-40578 and Osco 4354-MK mounting kits, giving buyers a straightforward cross-reference if their old kit carries one of those numbers instead of a Sierra part number.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-8505
• Product Type: Exhaust Elbow Mounting Kit
• Compatible Riser/Elbow: 18-1976-2
• Includes: 18-0897 elbow gasket, mounting bolt, mounting hardware
• Engine Fitment: GM Big Block V-8 454 cubic inch (Models 330, 340, 7.4L); GM Small Block V-8 305-350 cubic inch (Models 200, 228, 230, 260, 898); Mercruiser GM V-6 229 and 262 cubic inch (Models 185, 205)
• Finish: Machined
• Product Dimensions: 0.39 x 0.39 x 0.39 inches
• Weight: 0.24 pounds
• UPC: 808282127039
• OEM Cross Reference: Mallory 9-40578, Osco 4354-MK

Fitment

• GM Big Block V-8 454 cubic inch - Models 330, 340, 7.4L
• GM Small Block V-8 305-350 cubic inch - Models 200, 228, 230, 260, 898
• Mercruiser GM V-6 229 and 262 cubic inch - Models 185, 205

Replaces (OEM)

• Mallory 9-40578
• Osco 4354-MK

Frequently Asked Questions

What is included in the Sierra 18-8505 mounting kit? The Sierra 18-8505 kit includes a 18-0897 elbow gasket along with the mounting bolt and hardware needed to attach the exhaust elbow to the manifold.

Which exhaust elbow does the 18-8505 kit work with? It is designed for use with Sierra's 18-1976-2 Manifold Elbow, a 4 inch hose elbow with a 7 degree down angle.

Does the 18-8505 kit fit small block and big block GM engines? Yes, the 18-8505 mounting kit fits GM Small Block V-8 305-350 cubic inch engines (Models 200, 228, 230, 260, 898) and GM Big Block V-8 454 cubic inch engines (Models 330, 340, 7.4L).

Will the 18-8505 kit fit a Mercruiser V-6? Yes, it also fits Mercruiser GM V-6 229 and 262 cubic inch engines, Models 185 and 205.

Is the 18-8505 kit interchangeable with any other brands? It is interchangeable with Mallory 9-40578 and Osco 4354-MK mounting kits, so either of those part numbers can be cross-referenced to the Sierra 18-8505.

How much does the 18-8505 mounting kit weigh? The Sierra 18-8505 Exhaust Elbow Mounting Kit weighs 0.24 pounds.

What are the dimensions of the 18-8505 kit? Product dimensions for the Sierra 18-8505 kit are 0.39 x 0.39 x 0.39 inches.

Can this kit be used with a different riser than the 18-1976-2? The Sierra 18-8505 kit is built to use with the 18-1976-2 riser specifically; a different riser or elbow would require its own matching mounting kit.

What finish does the mounting hardware have? The mounting kit hardware for part 18-8505 has a machined finish.

Is the Sierra 18-8505 gasket reusable or should it be replaced during installation? The kit supplies a fresh 18-0897 elbow gasket, so it is meant to be installed new rather than reusing the old gasket when mounting the 18-1976-2 elbow.