I’m trying to find a rack and pinion for my 1986 Nissan 300zx NA. Can’t find one in stock anywhere. Also I was wonder would it be better if I just rebuilt mine.

 

I was lucky and found a brand new never installed factory one on Craigslist for $240 near me. Installed it last Saturday, what a bear of a job that was, you need to create the space to remove/install the thing by lifting the engine (undo nuts that hold the engine mounts from below), then lower the subframe.
I'm pretty sure 300zx Parts For You webpage has a used rebuilt one. Also I noticed autoparts places sell rebuilt ones for not too much money ($150-ish), taking yours as core. I would not try the rebuild myself, I think it's tight tolerances, high oil pressure etc.