{"product_id":"head-diameter-1-590-in-stem-diameter-0-3136-in-o-a-4-923-in-2","title":"Manley 11661-8 Head Diameter: 1.590 in. - Stem Diameter: 0.3136 in. - O\/A : 4.923 in.","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","offers":[{"title":"Default Title","offer_id":51244617728315,"sku":"BBPB_11661-8","price":603.83,"currency_code":"CAD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0955\/5958\/2011\/files\/public_578e85b8-26ed-486c-95b2-0d8e25f3a8d6.jpg?v=1778481821","url":"https:\/\/performancepartscanada.ca\/products\/head-diameter-1-590-in-stem-diameter-0-3136-in-o-a-4-923-in-2","provider":"Performance Parts Canada","version":"1.0","type":"link"}