New ignition coil, hot negative battery cable?

[LuckyLightning]

I just installed on my 1962 235 a new ignition coil that had several good reviews.

I went to start it up and she fired up right away. Idle was rough so I figured it just needed to warm up, so I kept the choke pulled out and I let it go for about a minute and as I exited the cab it finally stalled out.

Okay, no problem. I go to fire it up again...

Nope. Engine turns and turns and turns, but it's like there's no spark.

As I'm taking a look at the coil under the hood, my arm happens to graze the (exposed) negative cable where it attaches to the battery terminal, and it was hot! I touched the positive and it was fine to the touch. Both battery terminals were also fine. I grabbed the coated section of the negative cable to remove it from the battery, and it was pretty warm also.

Anyone see this before? Could the coil be bad straight from the store? Or is it the wrong coil for my truck (even though the store website says it's the right fit)? Why on earth would the negative cable be hot?

One thing to mention: when installing the coil, as I was tightening the nuts on the terminals of the coil, the top "lid" rotated a little due to the torque of applied to the nut (which was not much more than a good-solid-tightening-up). Not sure if that does anything to the coil, but wanted to mention it just in case.

Also, not sure if this matters: I removed the original generator and upgraded to an internally regulated alternator.