Had to post an update today, 5/22/2022. If you downloaded the bins I had posted before today, Titled "02express5.7withS104l60e4x4 os12212156", Don't use them. I updated the first post with revised bin files that should be the same as promised. Long Story Short, the 02 Express van bin I used as a base to start from from the "LS_Based_Engine_Repository-master' zip file was corrupted. It doesn't look like it, everything edits fine, Checksums fine, Flashes fine. But when It gets flashed on, for some reason you cannot ever unlock the PCM Normally. Never figured out why, but had to start over with another 02 Express L31 tune(2500 this time) and segment swap the s10 4l60e4x4 stuff in. Should all be the same same as the first posted tunes, but no issues from these ones. IF you did download that tune bin in the first week and flashed it, you can unlock your PCM with the "ground pin method" like I had to do 47 times to figure out the issue and get a good unlockable flash running. I'll post up the link to that ground pin unlock info.

Credit goes to PeteS160plus
Original video https://www.youtube.com/watch?v=oGeMK6LvQck