1965 Barracuda Electrical mystery

The car has a false firewall and everything is hidden behind that. Just about have to pull the engine to get the false firewall out. Can not see the bulkhead pass thru or the fuseable link.
Ugh.
This is why photos help. Sounds like somebody did a lot of retrofitting. You are lucky since the 65 bulkhead connector was the best, with big dedicated "buss bar" feedthrus for the large ALT and BAT wires. They don't have the melt-down problems of later cars. 63 had similar feedthrus, but not 64. That is, if you still have the original connector.