Which NP241 transfer case gives a VSS signal for the LS computer and a working speedometer?

Here is what the documentation says. Each point links to its source; details depend on your exact computer, harness and transmission.

• LS Control System kit: The speed output will not function unless a vehicle speed sensor is connected to the ECM through the harness VSS wire. (Chevrolet Performance)
• LS Control System kit: The calibration's axle ratio is set to 3.42:1 and is acceptable for ratios from 3.08 to 4.11. (Chevrolet Performance)
• LS Control System kit: Tire diameter must be between 26 and 30 inches for the LS Control System calibration. (Chevrolet Performance)
• The SEN-01-128 recreates the missing high-frequency rate when converting to an older transmission with a mechanical speedometer output. (Dakota Digital)
• The SGI-5E recalibrates high-speed signals of 32,000-250,000 ppm for an OEM speedometer. (Dakota Digital)
• The SGI-5E recalibrates low-speed signals of 32,000-4,000 ppm for an OEM or aftermarket speedometer or fuel injection computer. (Dakota Digital)
• The SGI-5E converts a high-speed signal from newer GM transmissions down to a low-speed signal for a speedometer, cruise control, or fuel injection computer. (Dakota Digital)
• The SGI-5E converts an 8,000 ppm signal to 4,000 or 2,000 ppm to run an OEM cruise control or fuel injection computer. (Dakota Digital)
• The SGI-5E converts a 16,000 ppm VDO Hall-effect signal to 8,000, 4,000, or 2,000 ppm. (Dakota Digital)

Confirm against the instructions for your exact parts before wiring. More: Tach and speedometer signals in our tuning guide.