1990-1998 - 3.27:1(21), 3.55:1(23), 3.73:1(23*), 4.10:1(23*).
*23 tooth gear can be used but is not completely accurate. You must change the transmission drive gear to achieve proper calibration.
the number in parenthesis' is the tooth count.
20 = black
21 = Red
23 = White