I have a 95' LT1 with about 65,000 miles. I've had a valve cover breather on for about 10,000 now and have had no problems with it. I've been hearing conflicting things about the breather and what it does with taking away the vacuum and creating a small vacuum leak but then I hear that the breather lets the pressure out of the intake manifold and keeps it from potentially leaking or breaking a gasket. Also should I be checking the PCV valve at all since I have the breather. I've heard the PCV valve is not really doing anything if the breather is on. I guess the main question is "Is the valve cover breather taking away any power or doing any damage in the short or long term?". Thanks in advance.

 

theres lots of threads about this very topic just do a search for it, brent has alot of good information about this topic

 

If you add a breather, the PCV valve will still work, and you still need to check it for condition. The normal sytem pulls air in through the tube from the throttle body to the passenger side valve cover. If you added a breather, you should have plugged that line at the valve cover and at the TB. So all you did was let the air go in through the breather, rather than through the line from the TB.

The reference to a "vacuum leak" had to do with the fact that the air that enters through the line from the TB to the valve cover has been "metered" by the MAF, and since its returned to the intake manifold by the PCV sytem, it is included in the calculations the PCM makes for air/fuel. By using air that enters through the breather, the air is no longer "metered" and has the same affect as a small vacuum leak... no big deal... the PCM can easilly compensate for it with the long term fuel corrections (BLM's)

You aren't going to cause any real problems with a breather, as long as you keep the PCV valve functioning correctly.