2000 Ford Mustang No Music

Maybe some can help? I have a 2000 mustang with the original Mach 460 factory radio and CD player and factory amp that I am trying to replace with an after market system. I would like to keep the factory amp and add a JVC KD-G820 radio/cd player. However, I can not seem to find the right harness. With the Mach 460 system the amp is powered out of the back of the stock CD player. The JVC player does have a single power line but I also need one for my sub. Could I just splice the amp power line? Maybe someone has already been there and does this I hope.