1970 Dodge Dart 408 with a T5 transmission? Can it be done?

Ok thank you for all of the input so far. Soo I figured I'd go with the T5 cause it seemed relatively easy to put in...but can it be built up? What is the next easiest but stronger 5 speed transmission to install? tremec, G force, or A5 T5, I did look at a T56 also, would that have a lot of work involved? I actually think i'm floating above 400 ft/lbs of torque when I mentioned mild* too....
Thanks,
-ANTHONY