If it's a '68 engine, the PCV doesn't mount on the valve cover. The PCV plugs into a rubber grommet in the valley pan under the intake manifold. The hose on the PCV goes to a fitting in the intake.
The hole in the valve cover takes another rubber grommet where a steel vent tube is inserted and the other end of the steel vent tube goes to the passenger side of the air cleaner.
The fuel pump may have two lines going back to the gas tank. The larger one supplies fuel to the engine and the smaller one vents back into the tank. When I bought my car there was a hose on the vent line with a bolt in it. The fuel pump had been replaced with one that did not have any provision for the vent line. I returned it to a stock fuel pump.
If you want to keep it a 2 bbl, I have an air cleaner and the vent tube that I removed from my car and won't be using again.
Now I've got a Q-jet and an open element air cleaner. I put a retro-looking breather in the passenger valve cover.
