The HEI wire is on the ignition circuit and has nothing to do with the computer harness. It's on the basic harness that plugs in to the firewall on the driver's side. The computer control part of the stock HEI computer igntiton gets powered from the computer harness, but is not necessary on a car without a computer. So, the computerized HEI uses wiring from 2 harnesses, only one of which you will need to retain to run the car without a computer.