I am trying to reproject a dataset into NAD 1983 10TM AEP to map across Alberta in ArcGIS 10.5. The ESRI guide states to use either: (a) NAD_1927_To_WGS_1984_10 (b) NAD_1983_To_WGS_1984_8 The problem is neither of these transformations is available within the drop down selection in the 'Project' tool, what would the proper transformation use for Alberta?
If transformations are listed as supported but don't show up in a dialog, it either means the data extent doesn't match the transformation's or, more likely, the transformation relies on on-disk files that aren't installed.
Historically, we haven't shipped Canadian transformation files due to licensing restrictions. That should be changing within a year or so, but for now, you have to source the files yourself.
Once you acquire them, just copy the .gsb files into the ArcGIS installation's pedata folder's ntv2\canada folder.
Some links: where to place files
An earlier gis.SE question with some information (possibly duplicate).