Alternator Upgrade
Bought a used AD244 145amp alternator off eBay for $55 with 67k on it.
Bought a longer belt at AutoZone (Duralast 975K6).
So for $75, I now have a bigger alternator.

I'll have to stop by AutoZone and have them test it sometime to see what it can really put out.
(when I did this swap on my GMT400 with a new Duralast alternator ($200), it put out 200amps)
A 3/8" ratchet is all that is required to move the tentioner out of the way to get the belt off and on.
2x 13mm bolts hold the alternator in place along with a rear 13mm nut (that does not get re-used with the larger alternator). The original alternator had a 13mm nut holding the power cable onto it whereas the new one has a 10mm. Once everything is unbolted and unplugged, use a small crow-bar to push the alternator up and out.
There are some sleeves on the 2 13mm bolts. Use a vice-grip to clamp them slightly shut and move them so that there is more room for the alternator (towards the front of the vehicle). They will re-adjust themselves once you tighten the bolts back down.
Now repeat the process in reverse. Super easy to do and takes about 30min tops.
This alternator should be able to be found on any GM truck/van with the 6.0L or the RPO code KG3. I always just look up a '03 Silverado 2500 6.0L when going to the parts store.
The belt is the belt for the larger alternator available on the later GMT400's, but you can't use that alternator since it has a different plug.
Basically, by using the newer alternator, it only requires the longer belt and not changing the plug that goes into the alternator.