Without knowing which make and model Ford the Delco car radio came out of or is going into, the schematics for a wiring harness can be difficult if not impossible to come by. Below is a brief mention of the basic wiring colors used for car stereo wiring by Ford.
You need to be very careful when doing car stereo wiring. Because there are two browns and two grays in speaker wire, you must be careful to make sure to use the right colors with the right component of the head unit.
Any other wires that are there will be for accessories that are individual to the make and model of the vehicle. If you need more then the bare basic wiring colors, you will need the make and model of the vehicle as well as the model number of the radio.
If the radio has a green and white ground wire, do not use it for a ground as the wire is for radios that have volume control on the steering wheel, and using the wire as a general ground will cause the speedometer to malfunction.