From what I have read the SM-318 and SM-326 came with or without overdrives. The three speed that came in our old trucks can not have overdrive added to them because they are different than the above models. At least that is what I understand. The Borg Warner T85N's I have read came mostly in Fords but will bolt up to our old truck bell housings and are the proper length, but I am not sure if this is true or not. Especially after what "Apachefiend" said above. These old overdrive trannys are a little confusing sometimes! I have found a few different one to buy but I don't know which one to get.
1959 Apache 3200, Standard Cab, Big Window, Fleetside, 235/3spd, Original Paint
1964 C20 Standard Cab, Fleetside, 283/Power Glide, A/C, Pwr Steering, Pwr Brakes, NoSpin | 
