Manley Performance · New
Manley Chevrolet Big Block Exhaust Valve Kit - 1.800in Head Dia. 5.930in O/A Length, 0.3415in Stem
MPN 12343-8 · Store SKU man12343-8
Supplier stock checked 11/7/2026, 9:32:22 PM UTC. Adding a part does not reserve it.
Request a return within 30 calendar days after delivery. New parts must be unopened and unused.
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Product details
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. Manley Valve - Exhaust, Valve-S/D BRODIX SR20? 1.800, 5.930
Manufacturer fitment & guides
Check 12343-8 against the manufacturer’s application information below.
A manufacturer application guide is not available for this listing. Request the exact application from JuiceBuilt before payment.
Part-specific notes
- California Proposition 65: Y
