Both of my E bodies have the rear sway bar. One is a 1970 Barracuda Gran Coupe that originally had a 318-2BBL and the other one is a 1970 A66 Challenger convertible. I know the history of the Challenger since it was bought new and it is untouched since 1984, The sway bar looks very original. According to the fender tag it appears the A66 Challengers got the rear sway bar. Part of the package was "Rallye suspension." The sway bar looks very original on the Barracuda too but unfortunately I just decoded the fender tag and it doesn't say anything about it coming from the factory with a rear sway bar. I think the rear sway bar really helps these car drive and handle a lot better. I like my cars to be mostly original but no way I am taking off the rear sway bar.