What is the purpose of the oil restrictor and where does it go

[Tidybuoy]

I stumbled on this in the parts catalog and I was curious as to what this does and where does it go. Below is a photo of the Oil Restrictor, My '74 does not have one and I'm wondering if this would reduce the amount of oil that collects in the air box. My guess is that this helps oil vapor to drip back into the engine??

[E Sully]

It goes in the vent tube from the oil tank to the intake. It was not used on early cars like my '73 or your '74, but in later ones. I believe from 81 on. It offers a restriction in the pipe that reduces air flow so the engines do not stall when the oil cap is removed. I would think it also prevents excess oil from being sucked into the intake.
It is part 10a in the diagram from the PET for SC's.

[GH85Carrera]

Yea, it is not an OIL restrictor it is an air restrictor.

[Targalid]

76 did not come with this.