Hopefully others more knowledgeable than I will chime in, but here's my 2 cents: You should make every effort to identify what that AOD came out of. AOD's behind sixes don't use the same internal components as the one's behind V-8's making them far less desirable. 1988 and newer V-8 AOD's are considered the best. Truck AOD's have wider overdrive bands. AODE's which require a computer to run started to appear in some Ford models about 1990. The most important thing to engineer when putting an AOD behind a carbureted engine is the throttle valve linkage. (Fortunately Lokar sells one.) I assume your comet was made after 1965. Otherwise a taller-wider 351W and the rather large AOD tranny will be a tight fit. Good luck with the project.