For a start, go to a local transmission shop and see if they have the adapter you need; or, try a Mustang shop. Bring your old parts and new parts to use as a show and tell. It may be as simple as a new flare on the cooling line. Also, I note in my NPD catalog that theyhave a 90 deg line setfor67 and early 68, and straight lines for late 68 to 70. You may have gottena one size fits all replacement.
Jim