Hello there

i swapped a 1989 IROC L98 into a 1987 z28. The 87 has the bulkhead connectors under the dash for i believe the injectors and something else and the 1989 harness does not have that wiring. Can someone give me some pointers where to splice in?
Also the previous owner really hacked up the dual fan harness and the wiring to the fan relays. If someone has pictures or any other information for these harness questions i would appreciate it

Thanks