Holley eletric pump sometimes louder!! Like bad loud??

the high pitch may be from air pockets. I had a blue (with regulator) and it ran funny until it was solid fuel in the line. I could tell when the carb filled when the pump dropped RPM by like 1/2. And it was loud too, not black loud but noticeable. My Red leaked and I couldnt rebuild it for less than a new one. I would rather run a Walbro style inline with a big return line now, quieter, higher volume and they are available off Ford truck frames at the wrecking yard. Keeps fuel cool too as it recirculates/filters it constantly and keeps your tank clean.