I do not personally know nor have I ever heard of anyone adapting a Ford or Chevy automatic to a Mopar other than possibly on an older Hemi. Have you thought of a 904? I know they are physically lighter and smaller than a 727 and use less horsepower to operate. My brother has one on his 400 HP small block with a Gear Venders overdrive unit. He has run it hard for 30k miles so far and no issues. He often runs his truck at the local drag strip as well.

-EM