{"product_id":"manley-big-block-chevrolet-1-880-head-dia-5-354-o-a-length-severe-duty-exhaust-valves-set-of-8","title":"Manley Big Block Chevrolet 1.880 Head Dia. 5.354 O\/A Length Severe Duty Exhaust 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":51692034097425,"sku":"MAN11563-8","price":301.07,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0907\/7129\/2433\/files\/48848c00e871784319a2f846e181c633_e14e2549-41a8-495b-9e68-1001ec0c0b0d.jpg?v=1749579667","url":"https:\/\/emitperformance.com\/products\/manley-big-block-chevrolet-1-880-head-dia-5-354-o-a-length-severe-duty-exhaust-valves-set-of-8","provider":"Emit Performance Store","version":"1.0","type":"link"}