I have a 1991 Mustang Gt with factory speakers and a Pioneer deck. There is 6 factory speakers and I want to connect them all to the back of my deck and I don't want to connect any of the speakers to an amp. Is this possible?

 

it possible. Do you know if you have a "premium" system in the car? If so there should be an amp at the bottom of the dash that is octaganal with a bunch of holes? On page 2 of my cardomain page on my signature I go over how to bypass/integrate into the premium system although mine is a little different with the mach 460, but they are still the same. There is a bypass hrns in your car(the one I point to inside the dash on my page) but yours should be closer to the glove compartment.