ok I want to add a 4g ground wire to my 5.0 and the small strap that's already from the engine to the firewall is pretty hard to get to. I figured I leave that and put the 4g in another location. Where's a good spot to hookup to and get a good ground.
The secondary power ground is between the back of the
intake manifold and the driver's side firewall. It is often missing or
loose. It supplies ground for the alternator, A/C compressor
clutch and other electrical accessories such as the gauges.
Any car that has a 3G or high output current alternator needs
a 4 gauge ground wire running from the block to the chassis
ground where the battery pigtail ground connects.
The 3G has a 130 amp capacity, so you wire the power side
with 4 gauge wire. It stands to reason that the ground side
handles just a much current, so it needs to be 4 gauge too.
The picture shows the common ground point for the battery & alternator.