273 Commando PCV valve

Steve...thats the early version...'67 uses a rubber grommet to hold the PCV...

http://phoenixspecialtycoatings.com/uploads/2/8/2/5/2825131/8736163_orig.jpg?389http://phoenixspecialtycoatings.com/uploads/2/8/2/5/2825131/8736163.jpg?389
**Pic swiped from Leanna's page!**

I have a new grommet(correct one) and it fits the pvc in my pic above perfectly. Why is the pvc threaded??
IF the one from Leannas pic are correct for 67, why the heck is the grommet hole so big??
I really hope this doesnt turn into another "pulley thread"....:banghead: