Cylinder Flow Dart Iron Eagle Versus Stock "049"
Here's the intake flow of an "049" casting's good port (black curve) versus that of a 308cc Iron Eagle (blue curve). The "049" casting has had the benefit of a good valve job, allowing it to stay close to the Iron Eagle's flow at lower lift, but when the valve clears 0.400 inch, the Iron Eagle just runs away from the stocker. On the exhaust side, the seat/throat design of the port benefits from Dart's Pro Stock experience. The result is higher-than-average flow right off the seat, with a substantial increase over stock at high lift.