94 wiring harness vs. 97 (LT1)

I have a 94 LT1 in my 98 camaro right now. I through a rod in the motor so I need to swap a new one in. I want to run OBD2 for emissions reasons I was thinking about just swapping in a 97 Engine with a 97 PCM. Will the 94 and 97 PCM be wired up the same? I had a lot of custom wiring to get the 94 pcm in there, will it just be plug and play or will i have to rewire the whole setup?

you will need to add more wiring for the crank sensor, rear o2 sensors, and all the other emission stuff evap pressure sensor, ect, ect,

I understand that the harness will be different. But are the pinouts under the dash going to be the same where the pcm actually plugs in? Or will i have to re-wire the plugs under the dash?