Missing hose on engine oil stem
 

I have A 87 fc rx7. The problem I have is circled in red in the attached pictures. I’m not sure if I’m missing a hose or line and if so where it goes. When my car get hot enough it will start smoking for here. Im curious if it’s just a small hose that connects to where the back circle is in the second picture. If someone knows what this is to that would be great.
https://cimg6.ibsrv.net/gimg/www.rx7...4e26340cb.jpeg
https://cimg7.ibsrv.net/gimg/www.rx7...3655a6d57.jpeg

On a stock setup, there's a hose from the nipple on the oil filler tube to the rats nest (emissions rack). Looks like this has been removed / deleted from your car.

How would I go about plugging it up or replacing the hose?

you can just cap it off

The one on the filler neck helps keep moister out of the oil. With it capped, you will see what is called "lung mustard".

https://www.rx7club.com/1st-generati...ustard-935171/

Oil Breather