Sierra 18-8535 Exhaust Manifold Elbow Mounting KitSierra replacement exhaust manifold elbow mounting kit (blocked). Barr, Indmar & Marine Power Ford Small Block V8 302-351 cu. in.; GM Big Block V8 454 cu. in.; GM Small Block V8 305-350 cu. in.; Kit Includes: (1) 18-0476-1 Riser Block Off Gasket; (1) 18-4258 Pipe Plug; Interchangeable with: Mallory; 9-40173; 9-40770; Osco; 992-MK-FW; CRR-MK-FW;