1965 Auto Transmission Swap

Which engine? If you've got a slant, no. Smallblock, yes.
The OD Dakota trans won't fit an A body without crossmember/tunnel mods.
Your '65 has a cable shift linkage. The Dak does not, and they can't be made compatible. The swap would entail a floor shifter or a column swap to a "66 steering column with mechanical linkage.
The '65 uses a ball and trunion output on the trans, the Dak uses a slip yoke. With the appropriate shaft (which will need to be shorter, too) it can be made to work.
Will it fit? With enough time, money, a torch and a BFH anything can fit, but it's definitely not a bolt in deal. Is it worth the trouble? Only you can answer that.