Used 99-00 LS1 harness from an automatic (4L60E) combo from a Trans Am.  This is a mechanical throttle body.  The PCM connectors have some broken plastic tabs (photo#2), and there are a few cut wires near the throttle body area (photo #3).  Usable harness that you will need to do some minor repairs.

The item in the photo is the exact item being sold.