Manley Valve - Exhaust, Valve-S/D 1.625,+.600 1989-pontiac-firebird-esi6878223 Use on trucks that have

Use on trucks that have the UMI rear flip kit installed

50 state legal - CARB approved

dash rattles and quarter panel flexing

BMR Suspensions Tubular K-members drop weight and add loads of structural rigidity

Manley Valve - Exhaust, Valve-S/D 1.625,+.600 1989-pontiac-firebird-esi6878223 Use on trucks that haveManley 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