How many brushes does it have? If it's a 3-brush unit, it won't work with the 3-unit regulators used from the late 1940's on up. Does the housing have one diameter all the way from front to back, or is there a stepped-down section? The heavy-current generators with the stepped housing usually had a big rubber grommet around the front mounting bolt, especially the 45 amp ones used on Buick, Olds, and Cadillac. Most Chevy and Pontiac generators did not have the front grommet, and they were 35-amp rated.
Jerry
