Duster/Demon

I believe that the front ends are different, tailights, the duster has a shorter driveshaft and wheelbase by 3", fenders and interior, um these are just a few I know off the top... other than that im not sure.

So the Duster wheelbase is shorter than the demon?

No way, Duster and Demon, fastback style, are both 108" wheelbase. Same driveshaft for like driveline set up cars

The Dart/Scamps body style are 111" wheelbase. There is a fill panel in the rear footwells of the floor pan that extend the wheelbase.