Electrical Short - What Just Happened?!

Quick background info:

65 Valiant convertible 273.

6 weeks ago, I added a ready-to-run distributor, e-coil, electronic choke, Standard VR128 voltage regulator, and bypassed the ballast resistor. Also replaced all of the instrument cluster bulbs and cleaned contact points on the circuit board.

No problems whatsoever, until today. Here's what happened:

First startup of the day sounded like it always does.

Second startup hesitated, had a quick, odd clicking sound, then fired up.

Third startup had a longer fast clicking sound, then fired up.

Fourth startup attempt, and all electrical was dead.

I checked the battery, and it's got normal voltage.

Where do I begin troubleshooting this? I'm hoping that the clicking sound might provide a clue to someone out there who's much more experienced than this vintage car newbie.

Thanks!