Welcome to the thread Barry70GTX..
Good to see another 57Hemi swap going. There's only a few us known to exist right now. This is new territory for all of us. I see you grabbed a salvage engine/trans. I have a salvage engine as well (no trans). I'm going to use the 904 trans that I have. I was planning on using the tremec (Keisler) later on. Recently, I found another trans that sounds interesting. It's a beefed-up A518 (4spd OverDrive) with lock-up torque converter. The lock-up converter can be set up with pressure switches to shift in/out of OD automatically. No need for a trans computer. Here's the URL:
http://www.redrider.us/518_transmission.htm

Bob