Manley Valve - Exhaust, Valve-LS7 S/D 1.615 1987-pontiac-firebird-esi3246161 the 6579 is a true

the 6579 is a true high performance upgrade worthy of consideration

Spring notes: The springs are designed for Chevrolet small block engines

120" wall thickness steel sleeve to prevent crushing

Grade 8 hardware

Manley Valve - Exhaust, Valve-LS7 S/D 1.615 1987-pontiac-firebird-esi3246161 the 6579 is a trueManley 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 1400F, Manley exhaust valves endured 100 million cycles, while competitors failed after just