5.7L hemi swap into A-body

If using the 545rfe transmission, how does it work? I was under the impression this tranny was electronically controlled.

I've been reading a ton about the EFI hemi swaps and read that for $1000 you can get a wiring harness. Does this harness have the wiring for the tranny? DO you have to wire a switch for overdrive? I'd much prefer not to be switching things.

Riddler