I don't recall ever having one of these on my car. Any idea where it mounts and how is it fastened. Maybe a picture? Thanks!

Figure 12-19 in the 68 service manual.

There is a picture here that Jim posted. https://firstgenfirebird.org/forums/ubbthreads.php?ubb=showflat&Number=278389&page=1

The junction block is on the rad support forward of the battery.
The Batt. wire comes out of the alternator and to the 'BUSS' near the horn relay. The buss is a junction of wires soldered together going to the alternator, regulator, horn relay (and on to main power-up at the firewall junction) and to the junction block. From the junction block a wire goes to the battery positive and is what charges the battery. There is usually a fuseable link from the junction block to the battery and from the buss to the regulator.
I'll try to find some pics.

That's a pic of a soldered buss, I can't find a pic of the junction block right now.

A diagram of the junction block and it's location is shown here on bottom right of the 1st page:

First Gen Site Engine Wiring

Awesome! Thanks much, have to get one then.

If you don't have one what is the route of your battery charging wire from the alternator?

Well, I examined the radiator support area some more, and....Bingo, I do have the junction block! Was looking for something bigger, but it is there! Thanks for all your help!

Another happy ending.