I'm currently on the fence about either upgrading the 360 with heads and a cam, or focus my energy on rebuilding a 6.1 Hemi I have laying around.
The Hemi needs new pistons, machine work, and electrical work in the car. Oh, and probably custom welded headers.

In the end the 360 will be cheaper, quicker and easier to upgrade, but a 6.1 Hemi in a daily driven Dart should be fun either way.