[AC TC]

I assume you have retain the factory set up. ( one pcv to intake and one hose to aircleaner )
Factory valve covers have large baffles inside, aftermarket usually doesent.
You can also istall a catch can on both lines.
Dont stuff things in the breather, they have to breed....
The old mopar v8 can that was used in the 70´s was a beautiful piece of function
and the will probably fit in your covers but you will have to adapt your pcv valve to it some way.
Excessive blowby is normal on a new engine but it should settle down within a couple of hunderd miles.
- I hope you havent gradma the engine during break in...

 

[AC TC]

PCV valves always goes to intake or carb base, unported vacum.

 

[AC TC]

This is one oldie but goodie mopar designed piece wich works really well..
http://www.carid.com/1977-chrysler-le-baron-engine-parts/gates-engine-crankcase-breather-cap-20823872.html

 

[AC TC]

"the leak down test was around 30%."
- this is high, talk to the engine builder.