The __________ should always be the same size or slightly larger than the cylinder head port diameter.

• A. Header
• B. Primary
• C. Throttle Body
• D. Intake

Answer: (B)

Matching the size of the exhaust path right where it leaves the cylinder is crucial for smooth, efficient flow. The part that connects directly to each cylinder’s exhaust port—the primary tubes of a header—should be the same size as the port diameter or just a bit larger. This creates a seamless transition from port to tube, preserving exhaust gas velocity and promoting good scavenging, which helps maximize power. If the primary is smaller than the port, it becomes a bottleneck that restricts flow and hurts performance. Making it significantly larger than the port doesn’t provide meaningful gains and can complicate design and fitment. The other options refer to different parts of the intake or a broader assembly, not the direct port-to-tuture relationship described here.