To those that want to stay stock but do not care about "Hidden" changes, the '58 thru '64 Custom, fairlane, and Galaxie T-85 w/overdrive is the same as the '57 Bird T-85 w/overdrive with the following exceptions: The Bird offered a close ratio and was shorter then the Passenger T-85 O.D. by 6" (Same as in '56/'57) also the '56 & '57 T-85's had a 10 &; 1" clutch disc where as the '58 thru '64 used a 23 &; 1" disc. so just change the clutch disc. and the shift arms on the side of the cover were exclusive to Thunderbird and different on the passenger car. So if you want a T-85 with or without overdrive and do not care if it is close ratio or year correct (They look exactly the same) then use a later one. They are everywhere because most people do not realize how useful they are. Me, I will stay stock. 312T85Bird

What?