dodge vs. plymouth???

I too, always thought plymouth was marketed, as an entry level car compared to dodge? My best bud argues that its the other way around, making me second guess myself. But going way back, I believe ply. was making cars, while dodge was still only building trucks. I would sure like to know the truth, on the subject. IMO I think the 40`s/50`s ply.`s looked better than dodge. With exception of the 70 E bodys. Example, the neon. was`nt the ply. cheaper than the dodge? Any chrysler historical professors on this site? Hope my buds wrong, lol, cause he`s a chevy guy.