What do the shapes of Africa and South America indicate about continental drift?

Nothing. The shapes are suggestive, but it is quite possible that they are entirely random. Anybody who suggests a connection has to prove it. That proof is offered in the "expanding Earth" theory, but that is awfully hard to accept.
www.youtube.com/watch?v=oJfBSc6e7QQ&list=PL5A1097F4E958728D

Plate tectonics makes the same claim but offers no evidence at all. Plate tectonics is accepted because scientists would rather be wrong than uncertain.