Performer manifolds are dual-plane, low-rise intake manifolds with a 180° firing order and patented runner design that you won't find in other brands. This patented design greatly improves torque over a wide rpm range, especially off-idle through the mid-range. Throttle response is excellent Performers are ideal for stock or mildly modified marine engines. These manifolds can be ordered hard anodized to prohibit corrosion in saltwater environments.