Non-turbo

1987    GMT 5203        B202
1988    GM 65101        B202
1989    GM 65102        B202
        GM 65103        B202, B234
1990-93 GM 65103        B234            4.45
1994    FM 51001        B234


Turbo

1986    GMT 5301        B202
1987    GMT 5401        B202
1988    GM 75401        B202
1989    GM 75301        B202
1990    GM 75402        B202
1991-92 GM 75403        B234            4.05
1993    GM 75701        B234            3.61
1994-98 FM 57101        B234 L/R        3.61
1995-98 FM 57001        B234E

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All 2.3FPT prior to `93 are 4.05 ratio, and from 1994 all 2.3FPT/LPT/Aero are 3.61 ratio.