Viton Stem Seals for High-Performance BMW N63 & S63 V8 Engines Viton Stem Seals are engineered to prevent oil from entering the combustion chamber, ensuring optimal engine performance. Crafted from premium Viton material, these seals offer superior control and durability across the entire RPM range. Their compact design allows for clearance in small inside-diameter valve springs. Developed to withstand the extreme conditions of high-horsepower and turbocharged engines, these seals meet the highest standards of quality. They provide enhanced resistance to high temperatures, fuel, and chemical contaminants, ensuring extended wear and reliability in high-RPM or high-mileage engines. Replaces OEM Part Numbers: 11340039494113400544921134757882511347572451113475042711134761413411340150843 Contents: (16) Intake Valve Seals(16) Exhaust Valve Seals