78 dodge van doors interchangable?

from what years are the doors interchangable for a 78 without mods?

All of the B van doors interchange, except of course the slider and barn door types.

yes, but from what year to year?

The doors from the B series vans all interchange,at least up to 1997.In 1978 the door handles got a recess where the 1971-77 doors were surface mount.Later doors got the plastic handle,not sure the exact year but probably 1994 with the front/rear restyle.