[bigblockv6]

Here are pics of the correct factory breather that was used from 68-72, 73-74 used basically the same breather but it was a push in type because the valve cover was stamped out for a grommet. It is important to keep a breather on your engine and not just cap it off,the system will get pressurized and will blow the main seal. There are PCV valves threaded to one of the intake ports in each cylinder head and to service those requires removing both valve covers.