Swap the harness from the h23a onto the h22a, and use the spare connectors from the left over h22a harness to wire any sensors the h23a harness does not have such as the vtec solenoid. You really need a HELMS manual for the wiring (or do a search for the ecu pin layout), and other than that it should just drop in.

Check here for parts: http://www.hondaautomotiveparts.com/