[Shiny]

Originally Posted by lust4speed

If you are not incombered by smog laws it would be hard to argue that a proper breather in the valve cover isn't the best solution. The PCV system operates under varying manifold vacuum conditions and was originally plumbed to two intake ports on the Pontiac manifold with smaller 3/8" vent hose. The valve cover venting sometimes inhales when the PCV valve is doing its thing and at other times expels crankcase pressure under heavy acceleration. The car manufacturers must have had a reason for keeping it on the outside of the air filter element but I haven't an idea why they did.

On my '67 that I'm going for the box stock look I have the original snorkel air cleaner and the original tube from the valve cover. My other Pontiacs have an open element air cleaner and simple baffled breathers stuck in the valve covers. All the street cars have a working PCV valve since they help with keeping the valve cover area under breathers a little cleaner.

Originally Posted by "QUICK-SILVER"

Only true when intake vacuum is high enough to out run crankcase fumes.

No intake vacuum under heavy load and the crankcase fumes come out the valve cover vent.


Treed by Mick
Clay

Great stuff, thank you both!

Explains how a breather tube mounted outside the filter makes sense. Basically, air going into the valve cover is filtered by the breather element. Won't be as effective as the air cleaner but better than raw dust. As you explained, when the vacuum drops and air comes OUT of the valve cover, the breather tube will bring it close to the air cleaner, which captures the fumes.

So.....

Where can I find this Chevy (or any other) breather filter housing that clips on or clamps to an open-element air cleaner?

Mike

[Shiny]

Originally Posted by lust4speed

Is the drop base steel? Everything I've seen is aluminum. Source?

When I was looking, I ran across a few options that seemed OK WRT flow...

I ended up going with the Chevy that didn't fit but may revisit.

I attached some examples, I'm sure there are others.

[Shiny]

Originally Posted by J.C.you

Spliced a couple together with drop base, made this

Thanks. So you welded a "stock" air cleaner housing to a drop base and retained the "stock" connection for the breather tube, correct?

Nice!