I posted perviously about the dash speaker which has now opened up a can of worms unfortunately. It turns out that the original unit was modified at some point and all of the internals have been changed for a modern amplifier, AM/FM with aux plug etc. It still looks factory or will when installed, however, don't think I can use it unless it can connect to the factory wiring. I have replaced every wiring harness in my car and would like to keep everything as original as possible. Which means I would have to find a new AM 8 Track or get my old radio put back to how it should be, unless of course there is a way to get the right connections on the back of the radio to mate with all the new wiring.
FYI I was originally told that the AM radio plays through the dash speaker and the 8 Track through the door speakers, but now believe that all sound should just play through the door speakers.
It looks like someone tried to splice the original wiring harness with the new wiring harness at some point, but it's just a mess!