I have an OBD2 B18C1 in my OBD1 civic. All I did was use everything OBD2 for the motor except the ECU. I have an OBD1 P72.

I had to run the extra wires that my stock ecu harness didn't have (VTEC, VTEC oil, knock, and evap purge.. I think that was all). That's it. There's nothing to it.