Download the service manual for your Barracuda if you haven't already done so.
http://www.mymopar.com/index.php?pid=109Look at the wiring diagram on 8-142 and 8-143. It's best to print them both out and then tape them together side-by-side so you can more easily follow the wiring.
Follow the Instrument Lamp wire E2A-18 O from the fuse block area. 18 is for the gauge of the wire; O is for orange. You'll see that the wire goes to the T-shaped radio plug first. If you have a radio on that plug, the dial light should be on when you turn on the ignition. If you don't have a radio on the plug, test for 12v with a meter on the leg of the plug that has the orange wire(s). If you don't have power, check the fuse. If you do have power, the problem is further on.
Above the radio, you should find a plug with a bunch of orange wires connecting. It is pictured on the bottom left of 8-142. One of the orange wires plugged in to the connector feeds the lights over the instrument panel. That wire may have come loose. Check for power with the meter in that plug. If you do have a connection and power there then the light bar (the black panel with the light sockets over the speedo) isn't grounded.
Let us know what you find.