Chrysler's A-Body (Unibody) Changes 1967-76

Thank you in advance for your time! It seems like Chrysler's base unibody (frame, Radiator supports, firewall, base dash (rally & standard)) used by Plymouth and Dodge were identical/unchanged throughout 67-76 production. Can anyone confirm this? Did the radiator opening dimensions for 6 cylinder VS V8 change or did the radiator mounting flanges take care of this.
1967-1969 Plymouth Barracuda
1970-1976 Plymouth Duster
1971-1972 Dodge Demon
1973-1976 Dodge Dart Sport
1971-1976 Plymouth Scamp
1967-1976 Dodge Dart