340 was only offered on Swinger 340 in 1970

There was a limited run of 71 and 72 340 swingers made for two? dealers in Canada

Purple was one of the more populars color in 1970 on A, B, and E bodies.

You don’t see them now because they are 50 years old and the 318 and /6 cars were not collectible 20-30 years ago so they got scrapped. Whereas the Swinger 340’s people held onto.

They also made 1970 Dart GT 2-doors with 318 that was also a high trim level. Might have had similar or higher base price as a Custom.