{"product_id":"manley-chevrolet-big-block-exhaust-valve-kit-1-880in-head-dia-5-522in-o-a-length-0-3415in-stem-1","title":"Manley Chevrolet Big Block Exhaust Valve Kit - 1.880in Head Dia. 5.522in O\/A Length, 0.3415in Stem","description":"Manley Severe Duty® Valves deliver the ultimate in strength, reliability, and high-performance durability. Engineered for extreme gasoline engine temperatures, these valves are crafted from exclusive materials (XH-428 for exhaust and NK-844 for intake), offering unmatched tensile strength compared to competitive alloys. In fatigue testing at 40,000 psi and 1400°F, Manley exhaust valves endured 100 million cycles, while competitors failed after just 100,000, proving a 1,000× longer fatigue life. Each valve features chrome stems, hard tips, and swirl-polished underheads with fully machined combustion faces for superior airflow, efficiency, and wear resistance. Built for those who demand race-winning strength and precision, Manley Severe Duty® Valves set the industry standard for performance and endurance.","brand":"Manley Performance","offers":[{"title":"Default Title","offer_id":67646611226897,"sku":"MAN11815-8","price":301.95,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0919\/3681\/7425\/files\/9f3fe65eab22c1b800b67cb4ba0de39eL_b439c30b-9f93-4659-a518-faaa5c629527.jpg?v=1791206281","url":"https:\/\/autoshopactive.com\/products\/manley-chevrolet-big-block-exhaust-valve-kit-1-880in-head-dia-5-522in-o-a-length-0-3415in-stem-1","provider":"Auto Shop Active","version":"1.0","type":"link"}