The name "Speed" is reserved for the Holley EFI Transmission ICF. Your VSS is from the custom Inputs/Outputs ICF.
You can configure the EFI software's Data Monitor (click "E") to include that custom created channel into one of the screen views.

Enter the Data Monitor/Datalogger Edit screen ("E" button at top left corner),
and "drag & drop" the custom channels over to the Data Screen/Log View lists.
You need to scroll to the right to select the custom created channels.