I have a LY6 and put fabricated valve covers on it. How can I vent the crank case

 

Use the LS6 or 2 valley plate for pcv. Weld bungs on the covers for breathers?? Run a vacuum pump. Short of cutting up your new covers. None that I can think of. I'm going to run some hoses to a catch can with a breather on the can. I 'm going to mount it on the fire wall. It will be neater then having the breather on the cover.