These Special Plugs and adapters are needed when you remove the vacuum pump on the GM LT Gen-V - 2014 & up engines. When the vacuum pump is removed, it exposes two passages in the oil galley. These passages are metric straight threads and they need to be plugged, or used for an oil pressure gauge, or pressure sensor w/ the Holley EFI system (i.e. Avenger, Terminator X, HP, or Dominator - Use Pressure Sensor 554-103 available separately or in Kit LT0004ERL).
