Here is a picture of the factory setup. It can be somewhat duplicated by using the original draft tube, cutting off the draft down tube a couple of inches from the riser tube, welding on a washer sized to a grommet that is sized to fit a PCV valve.
This mod has been discussed in this forum. Do a Search and you should find it.
Phil Moderator, The Engine Shop, Interiors and Project Journals
1952 Chevrolet 3100, Three on the Tree, 4:11 torque tube Updated to: ‘59 235 w/hydraulic lifters, 12v w/alternator, HEI, PCV and Power front Disc Brakes Project Journals Stovebolt Gallery Forum