Late model engine swap ?'s

[Imperial Kustom]

Hey guys! I have been wanting to do a late model (gen III & 4L60E) engine swap into my truck for some time now. I also recently aquired a '64 Cad 2 dr hardtop and would also like late model, fuel injected power for that as well. I know I can tackle all of the work except the wiring. I am a moron when it comes to these much more technologically advanced, non-carbureted, motor thingymajiggs. So, with that said, to all who have swapped in late model powertrains, what have you guys done to adapt the wiring harnesses to work with the earlier model vehicles? Please point me into the light!