The 400M had low HP ratings from the factory, but it has a 4" stroke, a 4" bore and is much like a stroked 351C w/a tall deck. That means the heads will flow adequately and if the right parts are used, the engine can make good power and torque.
But once you start talking turbos, I'm drawing a blank. You'd need forged pistons to be safe, and the set-up would take a good amount of fabrication- but it could be done, I suppose.
Another option is to use a bigger engine to start with, like a 460.