for 600 rear wheel

Hi I’m new here and I’m about to have a big problem! my beloved fzr 600 3he bj92 has been living again recently and my buddy and I want to rebuild it, now we are facing a problem what can be done with the back? most important is how do I get a bigger mature pure so at least n 180er and what do we need to do with it. which shwinge etc. we are grateful about every help