2dr post 68 Dart explain..

Post is a Chevy thing, Chrysler never called anything a "post". Just like Sure Grip not "posi", Mopar people are anal like that. The first roomy cab was coined as a Club Cab by Chrysler, they never made a Super Cab or Extended Cab...
Okay... how is “post” a Chevy thing? If you pick up any sales brochure from the 60’s all the manufacturers call these cars 2 door sedans..as far I know “post” was just a slang ...but if you have other information as to why it is a Chevy term I would like to hear it...