73 340 Compression Test interpretation help

I pulled the cover last night, and the hole will require special grommet (see pic), because of the thickness of the cover at the hole. Of course it is not available from a local supplier...

My Autozone/advance auto/o'brienms auto parts don't seem tpo have a twist in breather cap with a PVC opening, they only have a twist with no opening, or a push in.

Where would I source a twist in ith a PVC opening?

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