{"product_id":"manley-chevrolet-big-block-extreme-duty-exhaust-valve-5-522in-overall-l-1-900in-diameter-single","title":"Manley Extreme Duty Exhaust Valves – Chevrolet Big Block | Part #12739-1","description":"\u003cp\u003eEngine builders working with Chevrolet Big Block can use this Extreme Duty exhaust valve family to choose the required valve dimensions while staying within the correct Manley application group. The parent listing is distinguished by \u003cstrong\u003ePart #12739-1\u003c\/strong\u003e, which should be cross-checked against the rest of the engine combination.\u003c\/p\u003e\u003cp\u003eThe correct Chevrolet Big Block valve is the one that matches the finished head. Stem clearance, seat contact, installed height, spring package, and keeper location should all be checked during assembly.\u003c\/p\u003e\u003ch3\u003eKey Product Details\u003c\/h3\u003e\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eApplication:\u003c\/strong\u003e Chevrolet Big Block\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManley Series:\u003c\/strong\u003e Extreme Duty\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eValve Position:\u003c\/strong\u003e Exhaust\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eTitle Specification:\u003c\/strong\u003e Part #12739-1\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 12739-1\u003c\/li\u003e\n\u003c\/ul\u003e\u003ch3\u003ePackage Quantity\u003c\/h3\u003e\u003cp\u003e\u003cstrong\u003eSold individually.\u003c\/strong\u003e One valve is supplied per selected SKU. Order the intake or exhaust quantity required for the cylinder-head configuration being assembled. This quantity applies to the selected Manley SKU family shown on this product page.\u003c\/p\u003e\u003ch3\u003eSelection \u0026amp; Fitment Notes\u003c\/h3\u003e\u003cp\u003eValve fitment should be verified from the cylinder head itself; check the required head size, stem size, overall length, seat work, and valvetrain geometry rather than relying on engine name alone.\u003c\/p\u003e\u003cp\u003e\u003cem\u003eProfessional engine assembly and measurement are recommended. Product specifications should be confirmed against the selected Manley part number and the requirements of the exact engine build.\u003c\/em\u003e\u003c\/p\u003e","brand":"Manley Performance","offers":[{"title":"Default Title","offer_id":50207044665594,"sku":"MAN12739-1","price":64.26,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0325\/6352\/7739\/files\/1ecc177028ebb28898eba0253019ba05L_e3ac460e-39b6-4b29-a5e2-8a662a390650.jpg?v=1787979080","url":"https:\/\/lgcracing.com\/products\/manley-chevrolet-big-block-extreme-duty-exhaust-valve-5-522in-overall-l-1-900in-diameter-single","provider":"Legacy Racing","version":"1.0","type":"link"}