harold at Dynamic transmission can hook you up with a nice C-4 that will out perform a C-6......its less weight, less rotation mass inside the tranny, and should be a little cheaper to build.
A c4 uses roughly 25hp and a c6 will use around 60. You better be making some big hp and Tq #'s- otherwise its a waste of time.
SS93Cobra: FYI- a baby c6 is version that uses a small block bellhousing....they were made for 351's but I wouldn't be surprised if some 302 powered HD fords got 'em too. They are most definitely for small block applications.