This is a replacement cover for the B58 PCV system. This is not used to delete the diaphragm. If you'd like to replace the stock cover with something cool and billet this is what you need.
If you feel you need external vacuum for the PCV system, you can add a fitting on to the cap to run it to the intake.
We can include a new PCV diaphragm if you need it.
All cover will come with a billet cap.