My experience is strictly with a Chevy alternator, so YMMV!
The alternator in the '57 Chevy (yes, it replaced a generator) is from a
much later car, and has three connections: earth, battery, and sense. The
sense is a low current lead that allows feedback to the regulator. If the
sense wire is not connected, the alternator will just supply full voltage
(18v) to the battery, and rapidly cause smoke loss.
Try checking the wiring, and use a schematic from an example of the donor
car. I copied a few pages from the later Chevy manual, and inserted them
in the appropriate section of the service manual for future reference.
Good hunting! sf
Stan Fickes '65 Austin Healey Sprite
Software Engineer '57 Chevrolet Bel Air
I-Cube, Inc. '51 MGTD, '25 MG 14/28