Where's this noise coming from?

My 72 Duster with 318/904 has been making a high pitch rattle lately. It almost sounds like the sipping of the last bit of soda from a cup with a straw, but more like a high pitched rattle. It occurs when accelerating and above normal engine load (hills). Regular cruising is quiet but I feel a slight and inconsistent surge that's not unlike warped brakes. There's also clunk and jerk when changing gears from P or N.

I'm no pro, but my gut is telling me it's the torque converter. Ideas?