{"product_id":"manley-chevrolet-big-block-exhaust-valve-kit-1-600in-head-dia-4-921in-o-a-length-0-3415in-stem","title":"Manley Chevrolet Big Block Exhaust Valve Kit - 1.600in Head Dia. 4.921in 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":51625257992488,"sku":"MAN11551-8","price":301.07,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0952\/0218\/1416\/files\/71a7d21fe2bd56432946b3dfa742c46bL_cb6dea1b-9a43-4141-85a0-9d7036baa7ed.jpg?v=1775417973","url":"https:\/\/shop.paradigm-automotive.com\/products\/manley-chevrolet-big-block-exhaust-valve-kit-1-600in-head-dia-4-921in-o-a-length-0-3415in-stem","provider":"Paradigm Automotive \u0026 Performance Shop","version":"1.0","type":"link"}