the basic swap is easy, you do need the front cover and the oil pan from the early engine. they just bolt in place of the new stuff. same with the flywheel/flexplate and bellhousing. just remember to match the bellhousing with the tooth count on the flywheel/flexplate. for instance if you are going to tun a later model AOD with the later model engine, you will need to use the 50oz balance factor flexplate that has 164 teeth. if you are going to use an earlier C4 or top loader four speed with the earlier 157 tooth bellhousing, then you need the right tooth count as well as the right balance factor.
as for the fuel injection, there are a few ways to go. you can adapt a stock wiring harness for the later engine, kind of tough to do though
you can get an aftermarket harness, easy to use, but can be expensive
or you can use any number of bolt on efi systems, some simple, some hard
or you can build your own system using the megasquirt system, and a mix of factory ford and gm parts.