Does anyone know if adding a air breather (the little air filter on the heads) adds value in performance?

 

not sure about todays motors,but IMHO is that it won't work in due to emissions and other epa regulations. Looks pretty though.

 

Im not sure on the 3V , but I know that on the old 2V motors, it could cause a lean condition on that side of the motor. Due to a sensor , I forget which one , not getting the correct reading. It doesnt add any performance either.

 

on my yukon it set a CEL. waste of money, they sell them in autozone for the ricers.

 

Breathers are carburetor era components. Pre-emmissions cars used them to passively vent crankcase vapors into the air, and some breathers had tubes running down the backside of the block that would use air draft under the car to suck out the vapors. By the late 60's (my vintage of actual expertise on Ford Engines) factory air cleaners had a hose fitting that ran to the factory breather cap, to provide an inlet for air to run back through the PCV valve (for crankcase vapor ventilation). When people got rid of the factory cleaner, they needed to put a filtered breather on the valve cover to keep dirt out. Breathers never provided performance gains by themselves. They were needed to cap the valve cover when non-factory air cleaners were mounted, or the PCV system was removed. I've never been a fan of removing the PCV system completely, because it does help get explosive vapors out of the crankcase, and they are safely burned with the fuel charge. I never saw any real performance changes with or without the PCV valve (except when it clogged, and my car barely ran at all). I will submit the caveat that I always ran street motors, so full racers may have good reason to remove the PCV system that I'm unaware of. Since I assume you run your car on the street, and therefore have to get it inspected annually, I'd pass on the breather and spend my dress up money on something else.