This is the Autolite Style Voltage Regulator, 6 Volt and 31-37 AMPS. Negative ground, 3 terminal. Reference generators; GDZ-4817A, GDZ-6001D, GGW-7404A. Fits:
1948-1951 Willys Jeepster
1946-1958 Willys Station Wagon
1947-1958 Willys Pickup Truck
1945-1949 CJ2A
1948-1953 CJ3A
Note: This is for the Autolite style generator only. GDZ-4817A, GDZ-6001D, GGW-7404A. The Autolite is usually found on earlier vehicles.
I have a 4L 134 from a 42 MB and this pully doesn't fit the timing cover. pully can't seat all the way due to interference with the ring on the timing cover,