14.10.C. The air intake system up to, but not including, the engine inlet
may be modified or replaced. The engine inlet is the throttle
body, carburetor, compressor inlet, or intake manifold, whichever
comes first. The existing structure of the car may not be
modified for the passage of ducting from the air cleaner to the
engine inlet. Holes may be drilled for mounting. Emissions or
engine management components in the air intake system, such
as a PCV valve, or mass airflow sensor, may not be removed,
modified, or replaced, and must retain their original function
along the flow path.