I have an older (newly aquired) carburetted motor, I know the pcv scavenges gases from the sump, but how does the complete pcv system operate.

The motor in question is an RB30 nissan, there are 2 pipes off the roccker, one goes nowhere atm, the other goes to the inlet manifold, runs better since I plugged the pipe going nowhere, but where should that valve be etc.

any help would be much appreciated.

That should go to the filtered air side of things

Have a look at the T donk,the first hose in the rocker goes to the air in,and the back one is the one that has vacume and goes to the TB to get sucked into the motor

vik...make sense

Shoulda had a look meself, thankyou biggus Vikkas.