Odd behavior with timing light on cylinder #1

Greetings Moparians!

I started getting some carburetor backfiring yesterday, and am checking This and That in search for a remedy. I thought this particular set of symptoms most likely caused by air horn warp, but NOW have a wholly different hypothesis.

Just to make sure my timing had NOT slipped from the canonical 12.5 degrees BTDC I set this past March, I got out my timing light, put the pickup on the #1 plug wire, and got NO response from the timing light.

So, I checked how well...

Odd behavior with timing light on cylinder #1