The Edelbrock Performer EGR (Electronic Gas Recirculation) Intake Manifolds are dual-plane, low-rise intake manifolds with a 180 degree firing order and patented runner design. This patented design greatly improves torque over a wide RPM range for excellent throttle response, especially off-idle through the mid-range. The intake manifold directs the air or air-fuel mixture from the throttle body to the intake ports in the cylinder head. The flow typically proceeds from the throttle body into a chamber called the plenum, which in turn feeds individual tubes, called runners, leading to each intake port.