Pcv ??

"I have a set of M/T valve covers with a 1.5" ID hole. I found a 1.5" grommet with a 1" hole for a breather. Just nothing for the 3/4" PCV"

how thick is the valve cover where the grommet goes through?
Could try the dorman products web site, under pcv grommits, and look at the different sizes.
Good Luck.