90 chevy sb lt1 wiring onfo

Hi I have a 90 Chevy short bed have the lt1 and tranny bolted in I am using the nv3500 I have a wiring harness from a 95 Chevy caprice and comp s/n# 16188051 the difference I could tell is the plugin at the bottom of the oil pan near the front of the motor I got the whole harness back to the fuse box by the steering column don't think I need it all any way to remove the wires I am not going to use for the swap or what will I have to do to the original 4.3 harness in the truck.