I would not start wrenching on the 89 too much. Unless it is fully rebuilt in a lot of aspects. I'm thinking a lot of it still has stock parts on it, that may be original. I use to have an 89 w/a fully built zc motor and tranny. The poor thing started to fall apart from kicking down on the throttle so much. Maybe it will be different for you, but I would advise blowing so much $$$ on an old car that may start giving you problems if you start pushing it. IMO.