Tech: one-wire alternator swap, part 1

I want to upgrade the charging system in the '58 to an alternator. It came with a generator. A generator makes DC voltage, which is what the car runs on. An alternator makes AC, and then inverts it to DC. I don't know why this is more efficient (I am sure my friend EV-Steve could explain it in a snap) but nonetheless, cars have been using alternators almost exclusively for the last near 50 years, so that's what we're doing. This is a one-wire alternator, so called because it has an internal regulator, so it literally needs just one wire to go from the output lug to the battery positive terminal.
Here's the existing generator in place. I only had about an hour to dedicate to this upgrade, and after taking the generator out, I thought it would be easy to swap the alternator in it's place. I don't know why I thought that. I could see I would have to do some mild modifying of brackets and such, and so the upgrade would take more than one session.

Here's a sneak preview of the new alternator. Oooooh, shiny. More soon.