Manley Chevrolet Big Block Exhaust Valve Kit - 1.720in Head Dia. 5.354in O/A Length, 0.3715in Stem - 11553-8

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.

Features

• Proven fatigue strength for extreme performance
• Chrome stems and hard tips enhance durability
• Exotic alloys for superior tensile strength, reliability, and longevity
• Swirl polishing and machined faces improved airflow/optimized efficiency

Specs

• Manley Valve
• Exhaust, Valve-S/D 1.720
• Valve Length: 5.354
• Valve Head Diameter: 1.720
• Head Diameter: 1.720
• Product Market: Domestic
• Valve Tip Length: 0.220
• Tip Length: 0.220
• Margin Width: 0.065
• Seat Width: 0.100
• Top of Head: 6 Degree Dish
• Valve Head Shape: 6 Degree Dish
• Underhead Angle: 10.00
• Underhead Radius: 3/8
• Valve Series: Severe Duty? Series
• Valve Material: Stainless Steel
• Valve Type: Exhaust
• Product Type: Engine Exhaust Valve Kit
• Valve Quantity: 8
• Engine Valve Quantity: 8
• Industry: Automotive
• Out of Stock Message: Call for Availability
• Title: Manley Valve - Exhaust, Valve-S/D 1.720
• Prop 65 Yes/No: Yes
• Prop 65 (C, R or CR): CR