Does anyone know what kind of replacement speakers I can fit in my 1990 Sierra? They are supposed to be 5x7, but when I went and got new ones, they didn't fit. My two front speakers, which are the only ones I have left, are about to blow, so I need to replace them so I can have some highs in my system. I'm low on money, so building custom stuff for my truck really isn't an option right now. If anyone knows what size or maybe a specific speaker that I need, please tell me. Thanks