{"product_id":"sierra-18-3887-marine-head-gasket-for-mercruiser-7-4l-454-cid-gen-v-vi-replaces-oem-31136-pack-of-2","title":"Sierra 18-3887 Head Gasket - Replaces 27-75611 for GM 305 (5.0L)\/350 (5.7L) CID Engines","description":"\u003cp\u003eThe Sierra 18-3887 Head Gasket is a direct-fit replacement head gasket engineered for GM 305 (5.0L)\/350 (5.7L) CID marine engines. It seals the joint between the cylinder head and engine block, maintaining compression and preventing coolant or combustion gas leaks that can lead to overheating, loss of power, or engine damage. Installing a correctly specified head gasket is critical on marine engines, where consistent sealing under heat cycling and vibration keeps the powerhead running reliably.\u003c\/p\u003e\u003cp\u003eThis gasket is sold as a direct cross-reference replacement for several OEM and aftermarket part numbers, making it easy to source the correct gasket even if your old part was originally sold under a different number. It ships as a single gasket, ready to install as part of a head gasket or top-end rebuild job on a compatible GM 305\/350 CID marine engine.\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 18-3887\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Head Gasket\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eFitment:\u003c\/strong\u003e GM 305 (5.0L)\/350 (5.7L) CID engines\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eReplaces (OEM):\u003c\/strong\u003e 27-75611, 27-75611001, 27-48330, 27-34278\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 0.48 pounds\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eShape:\u003c\/strong\u003e Round\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eColor:\u003c\/strong\u003e White\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eUPC:\u003c\/strong\u003e 808282258955\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFitment\u003c\/h3\u003e\u003cul\u003e\u003cli\u003eGM 305 (5.0L)\/350 (5.7L) CID engines\u003c\/li\u003e\u003c\/ul\u003e\u003ch3\u003eReplaces (OEM)\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e27-75611\u003c\/li\u003e\n\u003cli\u003e27-75611001\u003c\/li\u003e\n\u003cli\u003e27-48330\u003c\/li\u003e\n\u003cli\u003e27-34278\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eWhat engines does the Sierra 18-3887 head gasket fit?\u003c\/strong\u003e The Sierra 18-3887 head gasket is designed for GM 305 (5.0L)\/350 (5.7L) CID marine engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat OEM part numbers does 18-3887 replace?\u003c\/strong\u003e 18-3887 is a direct replacement for OEM numbers 27-75611, 27-75611001, 27-48330, and 27-34278.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs the 18-3887 gasket sold as a single unit?\u003c\/strong\u003e Yes, the 18-3887 ships as one head gasket, not a full engine gasket set.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eHow much does the 18-3887 head gasket weigh?\u003c\/strong\u003e This head gasket weighs 0.48 pounds.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat shape is the Sierra 18-3887 head gasket?\u003c\/strong\u003e The 18-3887 is a round head gasket.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat color is the 18-3887 head gasket?\u003c\/strong\u003e The gasket is white in color.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eCan I use 18-3887 if my old gasket has a different part number stamped on it?\u003c\/strong\u003e Yes, as long as your old gasket's number is one of 27-75611, 27-75611001, 27-48330, or 27-34278, the Sierra 18-3887 is the correct cross-reference replacement.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eIs Sierra 18-3887 a genuine or aftermarket part?\u003c\/strong\u003e Sierra 18-3887 is an aftermarket head gasket manufactured to match the fit and sealing performance of the OEM numbers it replaces.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWill 18-3887 fit a 454 CID engine?\u003c\/strong\u003e No, 18-3887 is specified for GM 305 (5.0L)\/350 (5.7L) CID engines, not 454 CID engines.\u003c\/p\u003e\u003cp\u003e\u003cstrong\u003eWhat is the UPC for the Sierra 18-3887 head gasket?\u003c\/strong\u003e The UPC for the Sierra 18-3887 head gasket is 808282258955.\u003c\/p\u003e","brand":"Sierra","offers":[{"title":"Default Title","offer_id":48988169273563,"sku":"SIE-18-3887","price":75.09,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0839\/7586\/4539\/files\/SIE-18-3887_lg__16010.1558126722.500.750.jpg?v=1785188604","url":"https:\/\/www.goodvibesmarina.com\/products\/sierra-18-3887-marine-head-gasket-for-mercruiser-7-4l-454-cid-gen-v-vi-replaces-oem-31136-pack-of-2","provider":"Good Vibes Marina","version":"1.0","type":"link"}