The PCV (positive crankcase ventilation) creates a small amount of airflow and vacuum in the crankcase to remove
oil vapor, and burn it in the engine. This hose is routed to the PVC inlet on the base of the carb, and should be a 3/8" hose fitting. This distributes
oil vapors evenly to all cylinders. To restrict the airflow volume, put a small orifice restrictor in line with the PCV. The gapless ring folks recommend this because of the improved vacuum when using these rings.
The breather hose gets routed to the breather hose fitting on the air cleaner. This gets clean air into the engine. Buttoned up, this line is always under vacuum. When
oil vapors start coming out the breather, you have blow by taking place (ring seal). Some breather caps don't have this, and just inhale from ambient air. Meaning, it's nice, but not necessary.
The vacuum line for the brakes should not be connected to the PCV line. There should be a vacuum port on one of the intake manifold runners for the brakes. On the Edelbrock Performer RPM 351W, it's on the #4 runner.