Dash harness meltdown help

Definitely use a 65 bulkhead connector. Not only does it match your firewall opening, it is the only year they had dedicated lugs for the big ALT and BATT wires. If you have an extra one, PM me as I am currently re-doing my 64 wiring and would like to upgrade (even though I must cut the opening more).

Your wiper switch photo looks just like my 64 Valiant convertible. I was surprised when I pulled it out and haven't found out what the rectangular box on the flying arm is. I was thinking maybe part of my convertible top wiring, though I don't have hydraulic cylinders. Your last photo looks like the wiring for my 65 wiper. It looks confusing because one wire is often for the windshield washer and another wire is just a 12 V feed-thru to something else (dome lights?), unrelated to the wipers.

I have some photos at home and can take more if you need, of either my 64 or 65. As I recall, the components in the 64 dash are in quite different places from the 65, which is why some of your wires don't fit. Best plan is probably to use the 64 dash wiring with your 65 bulkhead connector. The terminals can be released with a small screwdriver, which is good to do anyway to clean them. The two terminals in the 64 bulkhead used for the big wires (that melt things) are repurposed in the 65 bulkhead (at least one is, washer?) since those wires moved to the big feedthru studs. Compare a 64 & 65 wiring diagram (I recall maybe G & H terminals). You just wouldn't use those with your 64 dash wiring, and have them available for a future accessory. Unwrap the harness enough to remove the big wires from the 64 harness (unwrap to the soldered junctions) and solder in the big wires on your 65 bulkhead instead. Unlike most people here, you won't need to worry about a melted bulkhead (just melted ammeter connections unless you clean those good).