If you are going to replace your radiator you might consider replacing it with a 1992 era radiator. It is about the same size as the 1988 one but offers an open cooling system instead of the closed cooling system. Mine costed me about $135 (three pass instead to two) for the radiator and a few more bucks for the other parts required. You will need to replace your heater core valve and the existing water reservoir. The hoses (if still good) should fit them both and the tranny (and A/C) lines should align with no problem..
www.radiatorworld.com for new replacements