I have the early externally regulated GM alternator on my Suburban with an ammeter. I don't know it's amperage output but it pegs my gauge on start up. I know of no ill effects of that. And I've never heard of an ammeter causing problems in real life. Only heard the myths on here.

"It's just a phase. He'll grow out of it." Mama, 1964

1956 Chevy 1/2-ton 3100
1953 Chevy 6100 "The Yard dog"
1954 GMC Suburban Now with a new proud owner.