Try Standard Transmission & gear they had all the parts for a 55 to 62 overdrive 3 speed that I rebuilt recently.

Standard Transmission and Gear
1000 N.E. 29th street
Fort Worth Texas 76106
817-625-7109
1-800-783-TRAN Fax 817-625-0580

You will need to know what Trans you have such as Borg Worner - Saganaw etc.
Hope this helps
Tom