Would a alternator for 1991 caprice classic work on 1990 classic?

The alternator for a 1991 Caprice Classic is likely compatible with a 1990 Classic. However, it's not a guaranteed fit because there might be slight variations between model years or between Caprice Classic and other Classic trim levels. To ensure compatibility, compare the specifications of the original alternator (which can be found in the owner's manual or by consulting with a professional) with the specifications of the 1991 alternator that you wish to install. This includes specifications such as amperage, physical dimensions, mounting points, and other relevant parameters. If the differences are minimal or insignificant, it might be feasible to perform the swap. Alternatively, check with automotive parts suppliers or specialists to get guidance on what you need specifically for your 1990 Classic.