This Cummins exhaust manifold 3976789 for engine QSB6.7 6B5.9 QSB5.9 ISB 6.7L is an automotive replacement part manufactured by Cummins. It's a functional or structural component of a vehicle's drivetrain, suspension, braking, or electrical system, replacing a worn or failed OEM part. It is commonly in engine, drivetrain, or chassis repair and rebuild work.
