Mach 460 System Replacement


New Member
Jan 24, 2023
Hi there, just bought a 99 GT convertible and while the Mach 460 was nice back in the 90's, it's crap today and my first day I broke the CD player. So it's going to get replaced with a nice CarPlay headunit, which I planned to do anyway.

So my question is, everything I look up talks about bypassing the amps and how the tweeters are driven separately, so why isn't the go to resolution is to just install the new headunit and run speaker wire to each corner, use a crossover and just tap into the factory harness at the speakers? The whole amp bypass seems like a lot of work for no real reason and actually more work.

Am I missing something here as to why I would want to do the amp bypass over directly running new wires?

I'm also going to replace all the speakers while I'm at it.
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My wife's 96 vert was a factory Mach 460 car but when I got the car it had some crappy deck installed. Factory amps were still there, they just ran wires from the deck to the speakers. It sounded like garbage. I re-ran all the wires and replaced the speakers and Amps and put a sub in the trunk. It sounds pretty good for mostly used stuff I had laying around. Now a couple years ago, I bought another 96 tangerine coupe car to use as a commuter. Again it was a Mach 460 car but someone just replaced the deck and connected it to the factory amps and speakers. It didn't sound half bad. I was presently surprised. It just needed a little more bass, so I put a 12" sub and amp in the trunk. Did it sound as good as the stereo in the vert, no but it was a close second in my opinion.

I guess, if you have the funds, I would rewire and replace it all. If you want to save some money, maybe try the deck first and see how you like it. Oh and sound deaden the doors. The 96 coupe had dynamat installed in the doors and wow that made such a difference in the sound and best of all no rattles. The wifes vert needs some sound deadener in the doors bad. Next time I have the door panels off, I am going to use some of the left over killmat I have and hopefully quiet some of the rattles down. Good luck to you.
I had an interface in my 96 GT for it to work with the factory amps. In my opinion, junk the whole thing and start over. In my 03 Saleen I have a JVC head unit with Cerwin Vega 6x8s in the existing holes and a little powered sub in the back. It's not too bad. Won't win any contests but it's good for me.