My '63 with the 170 did NOT have a PCV valve nor any part of a system. All mine had, as stock, was a vented breather cap on top of the valve cover toward the front of the engine and a downdraft tube exiting the block just forward and above the oil filter. This tube ran straight down the block and dumped just beneath the oil pan line. :thumbdown:
I "created" a PCV by using a TransDapt valve cover (Summit), finding a size applicable PCV grommet in the HELP! parts section at Advance Auto, and talked the counter guy into letting me go behind the counter to their PCV bin to find one that fit the grommet and my routing plan.
I plugged the block hole by making an "expandable" rubber plug with a 1/2" thick chunk of rubber, cut to the same diameter, with a 1/4"-20 flat head bolt (head to the inside so its 82deg cone would serve as a wedge), truss washer (OD a little larger than the block port) and nylock (on the outside), all tightened to seal and retain itself. Since the new valve cover had a twist-on breather port, I used a sealing twist-on cap.
I originally plumbed the PCV to a plugged port on the carb spacer. Though I found the system blew oil back through the dipstick tube. I suspect my port is clogged on the inside and haven't pulled it yet for cleaning. Instead, I replaced the PCV with a plastic elbow of the same OD and plumbed that to the air cleaner just outside of the filter. The crankcase fumes enter the breather outside the filter and pass through before reaching the carb.
Not truly a PCV system, more or less a CV system. My oil blow-by through the dipstick was cured as well as the sometimes visible crankcase fumes (downdraft tube). I further added a rubber seal inside the dipstick handle by cutting a small disc of 1/8" thick rubber, same OD as the ID of the dipstick cap, and slitted it to slide over the dipstick itself and jambed it all the way to the top of the cap. To ensure the stick stays down in the tube, I spread the expansion a little further so that it would resist more traveling up.
I did this back in November and have had no problems.
I plan to rebuild the carb soon, once I pull it, I'll check the spacer. If it is clogged, I'll clean it an retry the first PCV route again.