My mother had a late 70s 2 door Datsun in the real early 80s. For some odd reason it kept having cam issues and it was a “good f****** luck” trying to find anyone who would even touch it. The few mechs that did didn’t really want to and honestly didn’t have a clue about it and probably why it was constantly breaking down. I remember all of them bitching about it being a pile of cobbled together Jap tin cans. Haha
There’s plenty you can do depending on what you have.
Swapping in new replacement coilovers, changing out the leaf springs for a 3 link… two trailing arms and a panhard bar.
Make it ride and handle a lot better.
Pulling the interior (seats, carpet, door panels) and trunk liner out and installing Dynamat or Boom mat then putting the interior back together. Spraying the bottom with a Line-X type bed liner. That’ll help with noise and helps keep the inside a little cooler.