Manley Valve - Exhaust, Valve-BBC S/D 1.940 1992-pontiac-firebird-esi4307584 Features on-car adjustability for additional

Features on-car adjustability for additional clearance and centering aftermarket rear ends

Our Double Adjuster is machined from 4130 Chromoly

square tubing has greater torsion resistance over tubular designs

crack and eventually turn to dust causing the springs to then rub against the bare metal control arms which will cause harsh vibration noises to transmit through the vehicle's chassis when driving

and valvetrain stability in today’s high-performance engines

Manley Valve - Exhaust, Valve-BBC S/D 1.940 1992-pontiac-firebird-esi4307584 Features on-car adjustability for additionalManley 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