Need help here!! Mach 460 related

The Mach 460 wiring harness is separate from the standard wiring harness, so your first presumption is correct; he'll likely have to cut the wrap. But, you don't take all the wiring. The Mach 460 has a separate wiring harness, and it's in two parts.

First off, does your 'stang have the Premium Sound System installed? If not, you'll have to route a lot more wiring to get the Mach 460 work. If you have the Premium Sound System, all you need to do is plug in the extra wiring and you're set.

If you're not sure if you have the Premium Sound System, remove a door panel and the door speaker behind it. Trace the speaker wire back into the door; you should find another speaker connector taped up on the wire. If you found this connector, you've got Premium Sound. If not, installing the Mach 460 will be a big PITA.

Here's a great URL for the Mach 460:

http://www.flemworld.com/Mach460/Mach.html

To remove the Mach 460-specific harness, have your friend trace the harness from the speaker tray in the trunk. There are two speaker plugs that go up by the window; leave those. You'll re-use the ones in your stang. There's a second wiring harness that leads to the left side of the car. Follow that one down the left side of the car all the way down to the driver's kick panel. Disconnect it there. Then continue tracing the same wiring under the dash, over to the Mach 460-specific amp under the radio. Disconnect this second part of the harness. That's it - the rest of the wiring will be re-used from the Premium Sound System wiring.