When sorting out grounding problems, one piece of info that is rarely emphasised is that the ground wire on a DC system should be at least the same size as the red supply cable from the battery, and continuous back to the battery. Unlike AC current, DC comes out of the battery, does the job its asked to do, and goes back to the battery. That is why shunts are installed in the return cable for battery condition indicators.Resistance is the reluctance of the electons to flow through an inadequately sized wiring harness to do their job. (think of water in a kinked hose--same thing) The alternator is part of this resupply equation. When getting into high output alternators, the mounting bolt is often times not an adequate ground. Stainless steel in NOT a good conducter of electricityy--dont use stainless on electrical connections. Any alternator that was designed to work with high output windings will usually have a 1/4" 0r 5/16" stud ,or a cap screw marked for negative, at the back of the body (unless it is an isolated ground alternator,thats a whole different story which does not apply here). This is where your main negative should originate, and maybe go to a heavy bussbar which has an insulated base. BlueSea make a neat 100 amp unit. All you other negatives can go to this bar, which is in the line back to the battery. Rinky-dink little pieces of 14,16,18g wire connecting components together do not contribute to a good system. Neither does trying to get a good ground on a powder-coat surface.
What I am spouting here is basic DC electrical theory.As they say on TV, check with your doctor before consuming.
