Call a local salvage yard ,they can locate one and also tell you if
different year engines interchange.

Most cities of any size have a distributor of rebuilt engines. The best
thing to do is contact one of them. Shipping costs will kill you purchasing
anything that isn't local. The engines in cars don't change in design as
frequently as you might think and most likely that basic engine was used for
many years with only the engine accessories being changed. If you hadn't
mentioned the fact that this particular car means the world to her I would
say you could probably replace the vehicle cheaper than a rebuilt motor will
cost. If you really have a serious desire to keep this exact vehicle and you
can not afford to purchase a rebuilt motor then as an alternative to
purchasing a motor from a wrecking yard (which always scares me becuase you
basically know nothing about the motor) you may be able to find a running
T-bird with a crappy body or blown transmission that you can get for less
than half the price of a rebuilt motor then just junk the rest of the car.
It isn't a perfect solution but at least you know the motor runs and you can
hear it run and if you have more man-power than money it could be worth
while. If you go that route really look out for stuff like smoke from the
tail pipe, listen for knocking, etc. It doesnt matter about the way the body
looks or if the transmission works, all you need is the engine.