:nono: to multiple posts that don't help.

You can put in pretty much any engine you want into a first gen, and there will probably be mount kits to let you do it. The brown top ZC is popular, the single cam VTECs not so much. You could even throw in any B-series that you want [minus the B20a]. Of course, with any swap you're going to need/want better suspension to cope with the weight, but you can get that stuff too.

Wiring harness stuff will depend mostly on what engine you use and what OBD series it is.