There are a lot of issues involved. Let me address a few of them. I should point out that when new the wire sizes used, while on the skimpy side, were adequate to the task.
* All or our cars have issues of corrosion in the wires, switches and connections.
* There are always two wires, one to 12v and one to ground. They both need to be good.
* The key heavy gauge wires are battery ground, engine ground and battery to starter. I use 4. (.05v drop per foot at 200A, each connection will also have about .08V drop, I also have two engine to chassis ground wires.)
* The slightly odd electrical system runs all non starter current through the ammeter. This is a fairly long wire where 6 would be OK. Assume 20 feet from battery to ammeter to radiator fans and headlights in front. You would get about .32v of loss which would be marginally OK. You would see the headlights dim when the fan turns on. I use AWG4.
On my build, I removed the ammeter, added relays and fuse blocks to the front, back and cabin. Run AWG 6 or 4 wire directly from the battery to each fuse block. I also added a 100A fuse at the battery (not in the starter line). I did not find any connections or switches that were not corroded or compromised in some way.
Ron
