I'll preface with I know next to nothing about electrical

Currently if I hook up the battery it will try to start. It needed a new ignition and key, so went ahead and replaced that. Didn't help with the problem. I am assuming that it is a fairly easy fix, but no more time tonight. It is a 66 with a 302 installed, but the wiring looks good coming out of the firewall. I didn't see any funny things under the dash, so thought I would see if anyone had any thoughts!
Here are some pics of the mess around the voltage regulator!
As always thanks for the help and hope all are having a great weekend!
Matt