The early mustang, falcon Sprint, and a Mercury or two would have had the 3-speed Cruise-O-Matic with the cast iron case. They aren't bad transmissions either if properly rebuilt. You just have to make sure it is the 5-bolt pattern from mid 63 to early 65. I think they were all PCT models (PCT-A, B, F, G, & H). I think the PCT-J series were 6-bolt.
There were 5-bolt C4 transmissions made in 1964 and early 65 likely for certain cars & pickups of the time like the Mercury Comet, Ford Falcon, Fairlane, and Galaxie models. They are rare and hard to find now days.