Mach 460 Crutchfield harness question

yes, it will work but you are going to be connecting everything at speaker level, not pre-amp

what that means is that youe head unit is already amplifying the signal and then it's sent to your OEM amps where it's amplified again

not the best thing for sound quality or OEM amp long term durability but it will work

a better idea would be to pay a few bucks for an adapter designed to plug into the pre-amp outs on your head unit and then to the OEM wiring harness

good call, well worth the extra couple bucks