NOS or top quality rebuild only.
I installed a 100 amp replacement from a well known auto parts store. It looked great, windings were identical wire size, fresh and properly consolidated, bearings new and tight...
It worked fine until the first time he turned plow lights on with cabin heater and wipers. Then it smoked and burned out.
Replaced it. Put an ammeter on it and started turning stuff on. At 60 amps, it started smoking. Scraped winding with pocket knife - rewound with ALUMINUM wire!!!
Returned it, and special ordered one rebuilt by Delco - cost more, but we turned everything on, and even added another battery as a load - got to about 90 amps, alternator got a little warm - no smoke - COPPER windings, like OEM.