Originally Posted by supershaft
IMO a properly damped, good manometer can't be beat. They are THE scientific standard. They are in fact Mother Nature showing you what is going on.
if you had used a Uni-syn much, then you would realize that a Uni-syn is a variable throat size dampened manometer.
as flow goes across veritable sized opening so one can measure all RPM range. air movement moves a plastic floater, which is dampened by it's own weight. if one wants to know air flow/volume of one carb is higher, lower or same as another carb. Uni-syn will reveal it for any RPM. don't be fooled by Uni-syn's low $25 costs. this is a quality tool that used to be the standard for balancing side draft carbs on old British Sports cars.
which is exactly how this Bacharach model MZF Draft Gauge works (from my manometers used for HVAC)