Chevrolet Performance Bow Tie Cylinder Heads are an ideal combination of street drivability and drag strip performance. They provide a broad power range with ample low-end torque, excellent throttle response, good mid-range torque and enough top-end power to beat your competitors to the finish line! Bow Tie Street Cylinder Heads have rectangular or oval intake ports. Rectangular intake ports are larger in volume and designed to enhance high-RPM horsepower. These heads are best for vehicles that see frequent drag strip action. Cylinder heads with oval intake ports are smaller in volume and designed for greater low-RPM torque. Oval port heads are best for street applications where lots of bottom-end off-the-line power is desired.