{"product_id":"manley-chevrolet-big-block-2-300-head-3415-stem-350-longer-severe-duty-valves-set-of-8","title":"Manley Chevrolet Big Block 2.300 Head, .3415 Stem, .350 Longer Severe Duty Valves (Set of 8)","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":47435984666838,"sku":"MAN11878-8","price":356.33,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0605\/9012\/9366\/files\/5f4b70fa0b8a870e0877005e4b8d1853_25a638d2-4c99-41d1-96f1-57d64ae15016.jpg?v=1762420178","url":"https:\/\/warautoparts.com\/products\/manley-chevrolet-big-block-2-300-head-3415-stem-350-longer-severe-duty-valves-set-of-8","provider":"War Auto Parts","version":"1.0","type":"link"}