Started the car, idle was a little rough...heard a tapping. Found the source, I first thought the bolt holding the coil down was loose. Took a look at it today in the light and notice the crack in the tin.

Any suggestions on how to fix before I get some liquid metal?

I had the exact same issue a couple of years back. I had a friend who was taking a welder's course and brought it to him. One of his teachers did a really nice TIG weld on it. You can barely see it.

lol, i did a really crappy mig weld on mine. serves its purpose...

Huh, I have a crack in the same location. MIG weld it when you get a chance to drop the engine. That's the easy method. For the sadist you can MIG weld it in-situ

Weld and grind or replace....my magic wand doesn't work on tin....

had the same crack once upon a time
the coil rips out when the smaller blue coil is switched for stock and its attempted to tighten it down.

yep.
mig and grind

brant