How to Identify your GM Alternator
Used on Buick, Cadillac, Chevrolet, GMC, Hummer, Pontiac, SAAB, Saturn
History of the GM Alternator

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10DN - 12 Volt, 61 Amp - 1963-1972

First Alternator used on GM Vehicles to replace old DC Generators. External regulator mounted on the firewall. First used in 1963 on the Corvette.

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10Si - 12 Volt, 22-72 Amps - 1969-1983

First internally regulated alternator used by GM. Replaced the externally regulated 10DN. Again, first used on the Corvette. Wasn't into full production until about 1962.

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12Si - 12 Volt, 78-94 Amps - 1983-1987

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15Si - 12 Volt, 85-105 Amps - 1982-1984

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17Si - 12 Volt, 120 Amps - 1986-1990

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21Si/22Si - 12 Volt, 70-160 Amps -

The 21Si and 22Si are near identical cosmetically. Internal differences are...

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27Si / Type 100 - 12 Volt, 100 Amp - 1973-1985

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CS 130 - 12 Volt, 100-105 Amps - 1986-1997

Upgraded from the 10Si and 12Si.

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CS 130D - 12 Volt, 100-110 Amps - 1994-Present

A retooling of the flaws found in the original CS 130.

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CS 144 Early - 12 Volt, 120-124 Amps - 1986-1995

Upgrade from the 15Si and 17Si. Same Bolt Pattern.

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CS 144 Late - 12 Volt, 140-145 Amps - 1991-Present

Used an upgraded bearing and battery post assembly

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