{"product_id":"sierra-18-1997-1-center-riser-marine-exhaust-manifold-replaces-barr-fm-1-83-fits-omc-pleasurecraft-volvo-283-350-cid-gm-v8-1968-1980","title":"Sierra 18-1997-1 Cast Iron Exhaust Manifold - Fits OMC, Pleasurecraft GM \u0026 Volvo 283-350 CID Engines, Replaces GLM 56230","description":"\u003cp\u003eThe Sierra 18-1997-1 is a cast iron exhaust manifold built for marine inboard and sterndrive engines that route exhaust through a center riser configuration. As the manifold carries hot exhaust gases away from the engine block and up to the riser, it has to hold up to constant heat cycling and marine moisture without cracking or corroding at the mounting flange, which is why Sierra builds this manifold from cast iron rather than lighter stamped alternatives. This manifold is designed as a direct fit for OMC 283, 305, 307 and 350 CID engines built between 1968 and 1980, Pleasurecraft GM 283, 305, 307 and 350 CID engines, and Volvo 307 and 350 CID engines, covering a wide range of small-block V8 marine powerplants that share this exhaust manifold bolt pattern and riser interface. It is finished in white and is sold as a standalone manifold, so it pairs with the matching riser, mounting kit, and gasket set for a complete exhaust rebuild rather than including those components itself. Boat owners typically replace an exhaust manifold like the 18-1997-1 when the original has cracked, rusted through, or is leaking exhaust or water due to age and salt\/fresh water exposure. Because it is manufactured to the same form, fit, and function as the original equipment manifold it replaces, it bolts up using the existing mounting hardware and gasket set without modification.\u003c\/p\u003e\u003ch3\u003eSpecifications\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Sierra\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 18-1997-1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Exhaust Manifold\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMaterial:\u003c\/strong\u003e Cast Iron\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor\/Finish:\u003c\/strong\u003e White\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFit Type:\u003c\/strong\u003e Universal Fit\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 36.2 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282243333\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross Reference:\u003c\/strong\u003e GLM 56230, Mallory 9-40110, Osco 994\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eOMC 283, 305, 307 \u0026amp; 350 CID engines, 1968-1980\u003c\/li\u003e\n\u003cli\u003ePleasurecraft GM 283, 305, 307 \u0026amp; 350 CID engines\u003c\/li\u003e\n\u003cli\u003eVolvo 307 \u0026amp; 350 CID engines\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003eGLM 56230\u003c\/li\u003e\n\u003cli\u003eMallory 9-40110\u003c\/li\u003e\n\u003cli\u003eOsco 994\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-1997-1 exhaust manifold fit?\u003c\/strong\u003e The Sierra 18-1997-1 fits OMC 283, 305, 307 and 350 CID engines built from 1968 to 1980, Pleasurecraft GM 283, 305, 307 and 350 CID engines, and Volvo 307 and 350 CID engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-1997-1 manifold the same as GLM 56230 or Mallory 9-40110?\u003c\/strong\u003e Yes, the Sierra 18-1997-1 exhaust manifold is interchangeable with GLM 56230, Mallory 9-40110, and Osco 994, so any of those part numbers point to the same fit and function.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat material is this exhaust manifold made from?\u003c\/strong\u003e It is cast iron, chosen for its ability to withstand the heat cycling and corrosion exposure of a marine exhaust system over years of use.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the 18-1997-1 come with mounting hardware or gaskets?\u003c\/strong\u003e No, the Sierra 18-1997-1 is sold as the manifold only; a matching riser, mounting kit, and gasket set are needed separately to complete an exhaust rebuild.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the Sierra 18-1997-1 manifold weigh?\u003c\/strong\u003e This cast iron exhaust manifold weighs 36.2 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat color is the Sierra 18-1997-1 manifold?\u003c\/strong\u003e The manifold has a white finish.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhy would I need to replace an exhaust manifold like the 18-1997-1?\u003c\/strong\u003e A center riser manifold such as the 18-1997-1 typically gets replaced when the original cast iron manifold has cracked, corroded, or developed an exhaust or water leak from age and water exposure, since these manifolds see constant heat and moisture cycling.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the Sierra 18-1997-1 a genuine OEM part or an aftermarket replacement?\u003c\/strong\u003e The 18-1997-1 is a Sierra manifold manufactured to match the fit, form, and function of the original equipment manifold it replaces on OMC, Pleasurecraft GM, and Volvo small-block engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan this manifold be used on both OMC and Volvo powered boats?\u003c\/strong\u003e Yes, the same Sierra 18-1997-1 manifold is designed to fit OMC 283-350 CID engines (1968-1980), Pleasurecraft GM 283-350 CID engines, and Volvo 307 and 350 CID engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the manufacturer part number for this exhaust manifold?\u003c\/strong\u003e The manufacturer part number is 18-1997-1, made by Sierra.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eDoes the Sierra 18-1997-1 require a specific gasket set?\u003c\/strong\u003e The manifold works with the exhaust gaskets and mounting kits designed for its riser interface; consult your engine's exhaust system parts to match the correct gasket set for the 18-1997-1.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988090335451,"sku":"SIE-18-1997-1","price":367.41,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/18-1997-1__55776.1727713188.500.750.jpg?v=1785188518","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-1997-1-center-riser-marine-exhaust-manifold-replaces-barr-fm-1-83-fits-omc-pleasurecraft-volvo-283-350-cid-gm-v8-1968-1980","provider":"Good Vibes Marina","version":"1.0","type":"link"}