I'm not really fond of the 70 Road Runners either. It was like a last ditch effort before a major styling change. Many car makers kept the same basic car design for 3 years before changing.
absolutely correct .....the impression I got from research is what is known as the 71 B-body style was actually supposed to have come out in 70. However, 69 was a extremely high sales year for the B-body line so it was a gamble they took to decide to either squeeze it another year and try to keep the momentum going or change. They figured it would work with the over flow of sales in 69. However some things that played into it not working was the new E-body line that made the boxy cars look old and the even the Surprise Valiant duster came in out of nowhere and impacted sales by cannibalizing sales within Plymouth. The valiant success was not even foreseen by bean counters.