I wrecked my 1997 z/28 Camaro beyond repair.I bought a1994 Z body I noticed that the wiring harness are different the 97s smaller.My question is whats the best way to do this swap leave the 94s wiring or change to the 97 wiring.My car was tuned and everything can i use the 97s ecm.I could use any help.

 

I'd change the wiring to the 97. The Opti has a different harness in 94, as well as your 97 is OBDII and a 94 is OBD1

 

try asking in the correct tech section. they're there for a reason.

 

What do you mean by "the wiring harness are different the 97s smaller."? The harnesses are extrremely similar, with the 97 having several ADDITIONAL connections that the 94 would not have:
-crank position sensor
-EVAP vacuum detection switch
-after-cat O2 sensor on each side

Other than that, the connections are all virtually identiacal. You can run the 97 engine on the 94 harness and PCM, simply by pulling the short Opti harness off the 97 and replacing the short Opti harness on the 94. For the CKP, EVAP vacuum switch and after-cat O2 sensors, you would simply not hook them up. No effect on the engine or the way it runs. You will also have to replace the 97's 100kOhm knock sensor with a 4kOhm knock sensor from a 93-95.