What motors will fit in a 1985 Honda civic without much maintenance?

You'll find a couple of engines from that series that will fit right in, as I believe there were three offered back then, but if you want to put in anything newer than '87, you'll need engine mount kits, plus a bunch of other conversions, like all the wiring and custom axles. I think Hasport has a kit for the B16 for this series, but only ever seen one pic in HondaTuning (I think). I have an '86 Si that's getting an engine rebuild and port/polish on the head. There aren't as many choices with this series, but there are some upgrade parts available, if you know what to look for.