The "LS Stuff" you're finding, does it look like this? Scroll down to where it says "Wiring Conversion."
https://sites.google.com/site/sloppywiki/everything-ls/4l80e-info
If so half of it still applies as you're doing it at the transmission connector, and that didn't change. You remove two pins, move one, and leave the other out. The only thing that's different from the instructions there is the two pins/wires you have to add at the PCM for the input speed sensor on the 80E. Our PCMs are different, so those pins are in a different location. That info can be found in the factory service manual for your year as mentioned. We don't have the '96 GM factory service manuals archived here unfortunately so you'd have to find one somewhere else to verify. My '97 C1500 4.3L was pins 7 & 8 on the gray C3 connector but that may be different on a '96 V8 PCM.
If you don't want to mess with the transmission connector there are a few companies that make 60E to 80E conversion harnesses that take most of the work out of this. You still have to dismantle one of the PCM connectors to add the ISS wiring but the harness kits include the ISS pigtail with connector already installed.
https://www.mrk-motorsports.com/store/adapters/gm-4l60e-to-4l80e-transmission-conversion-harness/
And yes, you will need to have your PCM tuned to control the 80E.