Want to put a magnum 5.9 in my 70 dart.

It’s basically the same as the LA motor. The differences are: block side motor mount bosses were added. The Assy drive item on the front of the block are serpentine belt. The cam was changed to a roller setup, the rockets are pedestal style and the oiling of the top end changed.

There is 3 options for transmissions from a stock form.

NP - a833 4 speed
904 “small” automatic
727 “large” automatic