You didn’t mention what year Dodge Challenger you’re working on, but we’re assuming it’s one from the most recent run from 2008–present. If it were a vintage one from the 70s to early 80s, then finding the OBD port would pose a bit more of a challenge—because there might not be one!
The OBD-II technology of today didn’t become standard across all makes until 1996. Prior to that there was OBD-I, and each maker often had their own particular type of port, which meant that mechanics had to have a bunch of different OBD readers. But OBD-I only came into the scene in 1988, so if you were working on a Challenger circa 1970 through 1983, then it’s unlikely to have much (if any) microchip action at all.