1973 Dodge Dart Sport

The blue wire is the hot feed to the choke relay located on the opposite fender.
The red wire #8 is coming from the output side of the ammeter in the dash directly to the battery.
You can see the matching black wire #8 entering the hole to the dash next to the red one. This black wire is run directly from the alternator to the input side of the ammeter in the dash. Running this larger size wire and bypassing all the intermediate connections greatly improves the charging system.