I run two PCV ,one in each valve cover, in my 518 C.I. pump gas stroker motor. I used a vacume T off the back of the intake that I drilled and tapped for a pipe thread and used a brass pipe nipple to hook the vacume hose to the T to I also run two breather caps, one in each cover. The PCV helps suck any condensation out of the motor once it gets up to temps as well as sucking any blowby fumes into the intake manifold, much better to burn them rascals up than to let them sit in the motor and cause acids mixing the water and oil together Besides adding the PCV opens up some more control vaume leaks, making the motor idle better with big cams