Those are heavier for sure. There's a lot of thin gauge steel and plastic parts in the new cars. Even so, the heavy ones get decent mileage because of the efficiency and the transmissions. I could put a 8 speed auto in my Swinger and probably get mid to late 20's for mileage. Same with a 6 speed manual in my 66 Dart 273 car. A 833 o/d will get mid 20's. The new cars may weigh a bit more because of all the safety features. They are also well insulated for sound than the old cars were. My 66 weighs right around 3000# where my wife's Buick Envision weighs somewhere over 3500#. I haven