Annoying ticking sound while driving.

Hey all, I wasn't sure if I should put this in the Engine forum because I'm not quite sure if it is the engine making this sound (Or trans). It is a 1971 Demon with a 340 and 4 speed (Non Numbers engine and trans). I don't know a whole lot about the engine and trans build other than they were rebuilt about 10 years ago to stock specs.

I have this ticking sound that has been bothering me that I've been trying to track down. While accelerating at around 2k to 3k RPM I can hear this rapid ticking. It stops when I let off the gas and starts again as soon as I hit it. It also stops if I give it half throttle and bring it up above 3k RPM. I don't hear it sitting still regardless of the RPM. I even went as far as bring it up to 3000 rpm on a lift in gear and didn't hear it.

Initially I thought it was something behind the dash or floor rattling but I think I've pretty much eliminated everything it could be including disconnecting the speedometer cable. So now I am leaning towards engine or trans. Below is a link to a sound clip that I recorded while driving (It should play in your browser). At about 30 seconds and 50 seconds you can hear it pretty good. I'm hoping someone will have an idea what this could be because it is really bothering me.