Camaro used a 3 channel stereo. All other GM vehicles I'm familiar with, both cars and trucks had 4 channel. A 4 channel radio will fit the Camaro perfectly but you get only R or L channel on the front, and the unused channel should have a 10 ohm resistor put across it or it will blow the amplifier in the radio. You can use 4 or 8 ohm speakers in place of the GM 10 ohm speakers. The 8s work quite well. The 4s kind of suck as they draw more power putting your amps at risk if turned up too high, and the impedance mismatch makes the volume control touchy. You can't turn it up hardly at all without blowing both yourself and the amps out of the vehicle.