Dynosoar

Interested

I agree it looks like a flanged nut. Not the right one. If it is pulkl the washer out and you should be fine. But you may be better off just getting the right nut. Dyno

Look like the nut you have is flanged , it might be thicker than the OEM one witch is not . If you use a thicker flanged nut with the washer it might be why its further out .

Almost NEVER need to replace, remove and clean as well as replace grommet. Grommet will be as hard as a rock be careful not to drop pieces into the engine. Soak old PCV in solvent and continue to use. If it is OEM it is a quality piece. Dyno

It is flat glass, maybe someone with the glass out can make a template and post it. most old school auto glass shops can cut one out based on a template. I have had this done with 40 series windshields.