Where is the factory ground for the rear amps ? Best grounding ?

[MustangLife]

For my aftermarket amp. I'm using a ground under the seat because I removed the seat belts and seat belt brackets with the rear set delete. Not sure if this is the best grounding point. My ground is unpainted to bare metal and tight. My amp is mounted on the back of the passenger side where the seat would fold down. I only have a 3 foot radius of course with the ground wire. Where is the mach 460 rear amps ground located?

Thanks
Josh

 

[TT Audio]

Your ground for the aftermarket amp is 100% acceptable. I have built many award winning sound quality competition vehicles, and have never had a problem grounding the amps to the seat belt bolts.