I recently installed a oil catch can. I used the two plugs on the back of the block. I ran both tubes to the vented catch can. No vacuum going to catch can.

The question is do I still need a vented filter on my valve cover or is it no longer necessary? I see some people "T" the valve cover port into the lines going to the catch can.

 

You can eliminate the 2 lens ff the valve cover if the crankcase is vented elsewhere