Manley 11803-8 Severe Duty BBC Exhaust Valve Kit 1.940" Head Diameter

The Manley 11803-8 Severe Duty® Exhaust Valve Kit delivers race-proven strength and durability engineered specifically for Big Block Chevrolet applications. Each valve is crafted from Manley's exclusive XH-428 stainless steel alloy, offering superior tensile strength over conventional competitive alloys. In fatigue testing at 40,000 psi and 1,400°F, Manley's exhaust valves completed 100 million cycles — a 1,000× improvement over competitors that failed at just 100,000 cycles. This kit includes 8 exhaust valves with a 1.940" head diameter, 0.3415" stem diameter, and 5.422" overall length, featuring a 7-degree dish head shape, 3/8" underhead radius, 12-degree underhead angle, 0.250" tip length, 0.075" margin width, and 0.085" seat width.

Key Features:

• Exclusive XH-428 stainless steel alloy for extreme tensile strength and longevity
• Proven fatigue life of 100 million cycles at 40,000 psi and 1,400°F
• Chrome valve stems and hard tips for enhanced wear resistance and durability
• Swirl-polished underheads and fully machined combustion faces for optimized airflow and efficiency
• 1.940" head diameter | 0.3415" stem diameter | 5.422" overall length
• 7-degree dish head shape with 3/8" underhead radius and 12-degree underhead angle
• Kit includes 8 exhaust valves

Manley Severe Duty® Valves set the industry benchmark for high-performance exhaust valve endurance, making them an ideal choice for demanding street, strip, and race Big Block Chevrolet builds. Designed for internal combustion engines operating under extreme heat and pressure conditions.