Load and heat

[Dead Parrot]

Eeek on phone!

What about the negative cables? If your negative batt cable is long, there might be a small benefit to going up one size. It has to carry the same current the positive one does.

Also, make sure all the grounds are a decent size. A #2 wire from the block to frame would make sure the ground side of the alt output has an easy path. If your main ground is that flat cable from the valve cover to the firewall, your load might be overloading that cable.

Maybe create a ground lug connection. A bolt thru the frame where both batt and engine ground meet.