A method and apparatus for enabling a vacuum insulated glass (VIG) window to be substituted for and/or replace a non-vacuum insulated glass window in an existing window assembly frame structure is disclosed. A width of a VIG window is substantially less than that of existing non-vacuum insulated glass (IG) windows (e.g., a double, triple or quad pane windows). A replacement stop is provided that compensates for the difference between the larger width of a non-vacuum insulated glass window and a VIG window which has a smaller width, thereby enabling the VIG window to be easily and cost effectively installed in existing window configurations originally intended for non-vacuum insulated glass windows. The replacement stop may be used in the manufacture of VIG window units and/or to replace existing and/or already installed non-vacuum insulated glass windows.