You will need to have to get your wiring switched to OBD-1 and also you will need to use an OBD1 or OBD0 ECU. The reason for this is because all the OBD-2 blocks had two crank sensers and when using an OBD2 ecu with an OBD-1 block (which only has one crank sensor) The ecu will be looking for the reading on the second crank sensor. Since the ecu will not be getting a reading from the second crank sensor (b/c it's not there) it can throw CEL's and cause the engine not to run at full potential (from what i understand) And trust me OBD1 P72 ECU's are not cheap. As far as physically dropping it in, yeah it will fit fine. Just be sure to use B series motor mounts. If i remember collectly you only need the rear tranny mount and the passenger side motor mount. I just bought the whole set off of someone though b/c it never hurts to use all new mounts. If you need a set i still have them.

Just FYI-the swap i had in my 4dr EK was a B16a3 with YS1 tranny, using a P72obd1 ECU.