27 Tooth Close Ratio Input [ snap ring style ]  and matching close ratio Cluster gear 28-23-19-17 will work back to 1957 if using a 30T 2nd speed gear on the main shaft , will work with GM case #s T10-1, T10B-1, and T10C-1, [ no T10D-1 cases] excellent condition original Borg Warner Gears USA made , any questions message me though Ebay