Folks interested in flow bench testing:
These days I can't hear worth a dip, but I do know a fair amount about flow bench testing and there are multiple ways to discern the stability of airflow in the cylinder head or manifold without hearing....
The cylinder head should be tested with the manifold and carb/throttle body attached so the "real" flow test is indicative of what the system is doing.
That kind of testing is a bit more difficult, but much more meaningful. From that flow data, potential power can be predicted as can the rpm at which peak power will occur. Measuring a load of intake manifolds is worth the effort. Unless one follows the outline that I posted previously. You might find some worthwhile tips in HPBooks,
Engine Airflow
Regards,
HB2
Dissident