PCV draw

The PCV valve on my 440 appears to be operating fine, pulling it with the motor running has it buzzing and the motor idles the same as when it’s in the valve cover. However, when I cover the end of the valve so no air flows through it the motor is about to stall.

Is this normal operation for the PCV to draw that much air?

The PCV valve on my 440 appears to be operating fine, pulling it with the motor running has it buzzing and the motor idles the same as when it's in the valve cover. However, when I cover the end of the valve so no air flows through it the motor is about to stall.

Is this normal operation for the PCV to draw that much air?