3rd gen radio installation help

[jdscofield]

Ok guys, I'm sure you are all going to yell at me, but hear me out.  I slightly cut my ralley dash to install a retro sounds car stereo.  I wanted a new stereo that fit in the stock opening.  I just had to trim a little around the main opening, but the two dials fit right in.  Any ways, my question is, when you guys install new radios, how are you wiring them in?  the original only has a red and an orange, no ground and I can't find any wiring diagram online pertaining to the radio.  Any help is appreciated.  I don't want to fry the radio.

[71charger_fan]

If it had factory rear speakers, there should be a four-way connector somewhere up under your dash with red/dark green/dark blue/violet wires coming into it. Red is right rear neg/dark green is right rear pos. Dark blue is left rear pos/violet left rear neg. Radio power was supplied from a two-way connector that should have two orange leads coming into one side and a black and a red going into the other. The first orange, the E2 circuit, comes from a 5 amp fuse that also supplies the instrument lights. The other orange, the E2B circuit, goes to a splice where other E2 leads go to various instrument cluster lamps. The black wire, D1 circuit, traces back to one side of the turn signal flasher. The red wire, which I believe has a tracer, is the X12 circuit goes to the 20-amp radio fuse. Although not indicated on the wiring diagram, the radio may have grounded through its case.

This information is from the '71 wiring diagrams. You didn't specify a model year.

I'm not going to judge you for cutting a rallye bezel.