Need a little help

Assuming that '65 is the same as '64 (I don't know that it is)...

The numbered connections are for lighting, while the lettered connections are for engine stuff. Horn wiring is lettered and washers (if you have them) are numbered.

If your bulkhead connector hasn't been hacked up, it has different nubs on the 2 connectors so you can't cross them (ie. numbers with letters)

If you look at the bulkhead connector on the interior side of the firewall, the pins should be labeled (1 - 8 and A - H).

Get a factory service manual and check out the wiring diagram, it should make things clear.