I would measure the voltage drops directly.

With running engine from alternator housing to negative battery terminal. If you think the voltage drop is too high, the you can narrow it down by measuring single segments:
alternator housing <> alternator bracket
alternator bracket <> body
body <> negative battery terminal
and find the culprit.

I had a drop of over 1 V between alternator bracket and body. Symptom was slow starting which felt like a weak starter or a weak battery. The actual cause were corroded surfaces where the ground strap attaches to the alternator bracket.

Also measure from the alternator terminal to the positive battery terminal. There is a cable directly, but you can test how good the connections make electrical contact. Do not measure on the lugs, but on the terminal bolt/post. This way you see how good they make contact.

 

@Discorama I am worried about drops the voltage at the alternator is excellent. It appears to be an issue at the body side, it appears to be the body ground that is the issue, but unless I am wrong that is just a ground block, unless there is a cable under there.

 

Engine ground strap to the body at the ds rear of cylinder head, then ground cable to alternator bracket.