Do you have a picture of this?

The PCV valve should be on the hose connected to the vacuum meter the crankcase vapor to the intake.

The PCV system on my 390 is
PCV valve in passenger valve cover next to firewall
Hose from valve to back base of carb
Oil fill cap on driver side valve cover with hose to air filter mounted in air cleaner assebly.

Putting the valve on the intake side of the system will not allow the system to function properly.