A833 NP A body trans ID help & intro.

it came out of a 1968 dart 340-in what year did it come out? for the first time? second time? I have a 1970 340 block that came out of a 1969 Dart in 1975 - no numbers stamped on side. original owner told me he did a lot of racing and popped the 1969 engine with 45,000 miles and got a warranty shortblock in 1970.