Need your opinion...72 duster..worth it?

Aspen k frame is different than the Duster k frame....did they just drop in the engine?
Don't know...all he said so far is that the whole engine,kmember and suspension (I assume just front) was transplanted from the 76 aspen.
Does this mean that the original frame was altered to take this?

The aspen that year had a different torsion bar setup, right?