An upper transition assembly is disclosed. The upper transition assembly may have an upper spacer plate extending from a first spacer end to a second spacer end. The upper spacer plate may have a base portion having a first width. The upper spacer plate may also have a projection extending from the base portion. The projection may have a second width smaller than the first width. The upper transition assembly may also have a lower spacer plate extending from adjacent the first spacer end to a first distal end disposed between the first spacer end and the second spacer end. The lower spacer plate may have a third width about equal to the second width.