What trans are you planning to use? AOD <img src="/forums/images/graemlins/barf.gif" alt="" /> or C4? The C4 will be alot easier in the long run. You may even be able to fid a C5 to fit so you can have a lockup convertor.
That dinky A4LD will not handle the 5.0L even if you find a way to bolt them together. I work on Ford Autos for a living and can't stand AODs. <img src="/forums/images/graemlins/notooth.gif" alt="" />