I got this online a while back, don't remember the source:
The Offy valve cover has no provisions for
PCV. None. It was designed in early '61 when
PCV did not exist, and has not been changed since that time. I've been on the phone a few times to Tay Offenhauser trying to gently push him in the direction of reworking the cover for easy compatibility with
all slant-6s made between '60 and '80, not just the first two years' worth of production. Thanks for the reminder to call him again (though he didn't seem all that interested in making any changes).
There are no internal baffles, which is a problem, 'cause it means even if you drill your 1" hole and put in a grommet with a
PCV valve, you're going to be sucking splashed oil into the intake tract via the
PCV valve.
Unless/until Offenhauser updates the part, the best way to install
PCV is to obtain a Stant 10078 (old # SO-78 ) or AC-Delco 12C26 breather cap:
View attachment 1716353191
Drill the Offy cover at the rear to accept the grommet for this capthat'll be another item to buy; it's a Dorman #42344 (breather grommet for 1970-1995 Chrysler products)and push the cap into the cover. This cap has an internal filter and a 1" top hole, so just snap a standard Chrysler
PCV valve grommet (such as Dorman # 42064) into the top hole and pop a standard Chrysler
PCV valve into the grommet, and you're all set.