I did this on my 1994 model, I left my entire harness off the 4.3 V6 engine under the hood,, I re used my original wires for the oil pressure and coolant temp and air conditioning , the transmission harness on the stock harness I cut off and all the other plugs that went to the old engine that I did not need I simply cut them off and placed heatshrink on the ends of the wire and tucked them back into the loom on the main harness, this was the easiest way to go for me..........