Lenght= 28 1/2", from bell housing face to end of gearbox, that little brass round thing.
Height= 16 3/4", Top of bellhousing face to lowest point of main case just forward of output shafts
Width= 16 5/8", longest distance across bellhouseing face
Bell houseing face to centerline of outputshafts= 7 1/4"
note: Mine is a R21 with renault bellhousing. I use a adapter plate to engine 1/2" thick.