Magnum/727 in a early A body.

Got the old /6 and 3 speed out. Three speed and drive shaft are the flange type ball and trunnion units.

We are installing a 5.9 magnum backed by a 904 and keeping the original 7-1/4 rear for now, with plans on installing a 8.8 later. Can I just install a drive shaft from a 66 abody with a slip yoke and call it a day?