a lot of people mistakenly call the USDM Integra D16A1 engine a ZC - the DOHC ZC engines first appeared in Japan in the 1st gen CRX Si and 3rd gen Civic Si models from 84 to 87 - they had a brown valve cover (and are thus referred to as "browntop ZC"), external coil, vacuum advance ignition distributor (distributor cap is perfectly round with coil wire in center), dual butterfly throttle body and driver's side engine mount on the front of the block (toward the radiator) - these engines are basically like the 86-87 U.S. Integra D16A1 (also brown valve cover), with better camshafts and can be identified by the engine identification stamped on the block, which said ZC and serial number beginning with the number "1" - the 88-89 Integras in Japan also had a DOHC ZC which was essentially the same as the "browntop", except they had a black valve cover, electronic advance ignition with internal coil in the distributor and different throttle body and different CYLinder sensor on the end of the exhaust camshaft - the identification on these engines was also ZC with serial number beginning with the number "5" - these engines are basically the same as the 88-89 U.S. Integra D16A1 (also black valve cover), except for the camshafts - any of these ZCs and D16A1s will bolt right into the 84-87 U.S. CRX/Civic if you use the 86-89 Integra transmission, axles, knuckles/hubs and shift linkage - the identification stamp on the "browntop ZC" and the 86-87 Integra D16A1 is on the back of the block above where the starter is located - for your purposes in swapping the head, you need the 86-87 Integra head if it has vacuum advance ignition and external coil or the 88-89 Integra head if it has electronic advance ignition - the internal parts of the heads (except camshafts) are all the same
this is where you find the I.D. stamp on the early engines
this is 88-89 D16A1 head on left and 86-87 D16A1 head on right - blue circles are bolt locations for the Cylinder sensor and red circles are bolt locations for the distributor