Actually in some cases it is BOTH the ammeter and bulkhead connector. The whole circuit is simply not heavy enough for heavy current applications. I melted the ammeter mounting bosses somewhat in my 70RR cluster way back in the mid 70's before Al Gore invented the internet. AND the same car suffered damage to the bulkhead connector terminals.
Even in 70?-72, some of the large sea barges used external shut ammeters which eliminated the problem. "Ma" knew the problem was there, as the cars with optional 65A alternators used modified harnesses to combat the problem. This is known loosely as "fleet police taxi" wiring. Look up in the 70--72-ish shop manuals, look up the optional 65A alternator wiring for the B bodies.
After I got out of the Navy (74) I saw a few Dodge ammeters melted from snow plow hoists, winches, or big driving lights. Looked EXACTLY like the photo in the MAD article, read it here:
Catalog
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