73-76 All -- This is where they started getting a lot heavier. Basically every group got a little heavier over the previous, but this is the porky generation, crash standards, emissions controls, and massive bumper assemblies took their toll.
This statement is a little overblown. The Dusters and Demons/Darts only varied in weight by a few hundred pounds from 1970-1976. I wouldn't call that "a lot" heavier for the newer models. And let's not forget the Dart Sport Light and Feather Duster models in later years.
Everyone seems to have a hang-up with the so-called "massive" bumper assemblies from '73 on, but they aren't THAT much larger than the bumpers on some earlier A-bodies (Don't believe me? Put a '69 Dart and a '73 Dart Sport side by side and compare). Plus, it was easy to remove the rubber bumperette assemblies.
Finally, horsepower ratings on the 340 V-8 didn't change from '72 to '73 (240 horses both years). And horsepower actually increased in '74 with the 360, which was rated at 245 horses.
