[VetteVet]

If you look at the picture I posted, The red wire junction is how the stock 67 truck is wired, it's mine. This is done so that there will be a shunt between the battery and the alternator for the ammeter gauge to read charge or discharge. The fuse block feed wire is also connected there and it runs to the firewall block and feeds the light switch, the horn relay, and the ignition switch as well as the fuse panel.

The alternator external regulator sensing wire is also connected to the junction. It's all in the diagram I posted in post 9. If you have a one-wire alternator then you can connect it to the junction and the ammeter should still work. If you have the idiot light then it will not work because it is no longer connected to the alternator field circuit and the diode trio inside the alternator, to indicate the alternator output or the battery state of charge. If your truck has been converted to the internal regulator alternator and it's a one wire, Then you can just connect the gauge wire you choose to use from
the stud on the back to the junction or to the battery plus or to the starter terminal.

The picture you posted shows the small jumper wire going to the no.2 terminal on the alternator so you do have the internal regulated alternator. The question is whether it's a one wire or three wire style and are you getting any output from the alternator. Check with a voltmeter between the large post on the alternator with the + lead and the battery ground with the - lead with the red wire connected to the battery. S/B 14.5 volts +or- a few tenths of a volt. If you get no reading then jump another wire from the alternator stud to the no.1 terminal very briefly, just touch the two and recheck for voltage. If you get a good reading then you will have to complete the conversion like the diagram in post 9.