[rpmerf]

What truck do you have? What is the alternator?

In converting the generator to a 12SI alternator in my 70 -
Run the big lug on the alternator to the driver side junction block. Think I used ~10 gauge wire.
Run the voltage sensing wire to the same junction block. Used like 18 gauge wire.
Run the exciter wire to the brown wire that was going to the voltage regulator.

Another issue - The top bolt is 10mm x 1.25 or 1.5. Needed a new bolt, and needed to grind the bracket a bit.

If your alt is on the passenger's side, it is not unusual to run it to the starter.