the D16A1 engine is not the same as the JDM DOHC ZC engine, only similar - almost the same as the 84-87 ZC, but completely different from the 88-91 ZC
the D16A1 engine will bolt right into the 1g CRX and 3g Civic, however, it will not bolt right into the 2g CRX and 4g Civic - if you were going to attempt it, you would need the 88-89 D16A1 and not the 86-87 due to the ignition system - you will need to fabricate a driver's side engine mount - the D16A1 mount is on the front side of the engine (toward the radiator) rather than on the end like the 88 and up D-series engines - you will need to do a slight modification to install all of the bolts from the transmission to the engine - you will need to make a modification to get the starter to bolt on - quite a bit of work for not much gain, but it has been done many times