Also, that heater valve on the firewall has a habit of sticking, or at least mine did on the 88 I had. Try pumping it by hand to make sure the the little metal bar on the bottom of it (should be easy to see what actually is supposed to move there) can move. Push it up a few times, see if that helps, always did for me. Sucked starting the car up in ~0°F weather, letting the car "warm up" and having no heat when you get IN the car...