What torqueflight 727 transmission rebuild kit do I need????

It sounds like this won't be a crazy build, but more of street cruiser, although not much detail was provided about the engine. In this case, skip the manual valve bodies and just go with a shift kit and the Transtar kit 70aarcuda suggested. At the power level I assume you'll be at, that is under 450 horsepower, a 727 needs nothing more than stock rebuilb with good parts, a decent torque converter, a good transmission fluid cooler added, and a shift kit will help.