the duster and dart were the "base models" of sorts...the demon was a performance package, but it was also offered with a slant six, whatever sense that makes.

the body style is the same as all a-bodies from 71-76, which includes darts, dusters, and demons...the front and rear were different, and the wheelbase is shorter...the demon has a 108" wb, the other models have 111, i believe.