Calling all tech heads, I have a problem!

Heres the scenario, I have a 1974 Mustang II hatchback with a broken radio. Now heres the problem, I want to try and keep as much of it stock as I can, but at the same time I want to install a head unit with an amp and subs. I figure the smartest thing to do in this situation is to install the head unit into the glove compartment and keep the radio as is. Is this possible?? Will I be able to use all the basic wiring thats needed to connect the head unit to the battery, the head unit to the amp, and the amp to the subs? I can go without using the actual stock speakers in the car because I don't want to mess with the radio. How would you guys go about doing this? Thanks a ton for any help!