FZR 1000 engine damage

Hello guys, I’m new here and I need your help!!! I probably have an engine damage with my 1000 FZR Bj. 89. Had it not run for a few weeks and when I had brought it back to run after several attempts, super much white smoke came out of the exhaust, which smelled like oil. The cooling water level also remained constant, but became quite hot. Now I am expanding the engine and I have also discovered a lot of oil on the spark plugs. Will the cylinder head seal be, will you? Can you give me now perhaps a few tips on how I can best make myself to the engine. What I should renew, check and consider. Where do I get the spare parts best? Thank you