AM/FM radio and wire identification

Heres link to repair I did on our 67. Gotta click on links for pics to show.
67 antenna repair
Agreed, red is 12V + power lead, Orange is 12V light power lead, Green is speaker +, Black is speaker -. The radio itself grounds through a support bracket attached to the radio housing and dash frame. For the radio to work properly, you also need a good antenna that is also grounded properly.

What Cudamark said. Often, the antenna grounding or inner cable is bad, which often results in bad AM and no FM.