66 barracuda ignition problem

Car: 1966 Barracuda
Problem: reoccuring issue, failed electrical connections before ignition switch, and after the relay, kills the whole car.

In the past 7 years this has happened 5 times, lost connections/continuity to ignition switch. the connection fails in a different place everytime.

First, factory splice in the "underdash" harness. (fix, bypassed the 4 iches of wire)
Second, burnt connector in the firewall connector (fix, replaced all male & female fire wall connectors and the bulkhead plug)
Third, ammeter burned out (fix, bolted all connections from the ammeter together to completely remove ammeter from the curcuit)
Forth, starter relay died (fix, replaced the starter relay also replaced the ignition switch)
Fifth, don't know where its failed yet, could be the Fusable Link, funny its the only thing on the system that hasn't burned up, and it supposed to protect every thing.

Any ideas whats going on? (i do understand Ohm's laws, to an extent)
Thanks