Lose the original tires no matter how good they look. After 17 years, the rubber compound has hardened to the point of offering just a fraction of it's traction capability. Once you do so, you will have a more accurate idea of it's current handling traits and can tune more accurately.
Change ALL fluids, including rear axle, brake and power steering. Loosening the differential fill plug be a trial. Look for a thread generated by Mike Tangas for further guidance. I believe the last post was just a few days ago, therefore just scan back a few pages on this particular forum.