Auto trans recommendation for 360 crate engine

B9850CE0-F662-4110-B314-B67A328394FC.jpeg The body shop that did our Barracuda is modifying a 1953 Dodge 1/2 ton truck. It now has a Mustang II front suspension and a 4 pt link diff set up. The owner plans for the shop to install a crate 360 (details attached). The question is now, what auto trans to use.

Owner and shop want an off the shelf solution that is as simple as possible. I recommended an A500 RH, but I don’t know where he could get one off the shelf, and walk them through the installation so that it works.

I told him if anyone had ideas, they would be on this site. So, recommendations?