Dart was there for the full year - Duster for only 7 months

1970 Windsor, ONTARIO production "0R"
Dodge c-body 8/69-11/69
Plymouth c-body 8/69-12/69
Dodge a-body 8/69-7/70
Plymouth a-body 10/69-4/70

the above 340 engine was a late November scheduled build - Dart or Duster