If you are talking about under the hood wiring,I would think you would want to use the 83 harness for your lighting. The 83 front clip has dual headlights. Correct? You would have to do a lot of splicing if you used the 78 harness. Use the 83 harness and plug it in.. You could probably use the engine side harness also. It may or may not have a few extra wires but if your existing wiring is messed up,I would use the 83 harness. timo22