The small Ford-O 2-speed is easily distinguishable by its small size and aluminum case. They were made for the Falcons and the Comet as well as other light duty applications that hit the streets in 1960. The 140 was a doggy little bugger so the 2-speed was all it needed to drag grandma to the grocery once a week.
One or two of the Borg Warner specialists use parts between the models to build a stronger transmission with a bit more longevity. They may recommend any sort of ATF but I will add this. Ford developed Type F fluid in 1967 for all of their transmissions up through the FMX series. The only exception is the C6 that came out in 1966. You can likely get away without using type F but it is a good fluid to use on the old transmissions that still contain the bronze & steel clutch packs. It helps them engage better without slippage. Use it or not but if it slips, a change to Type F might help that since that is what it was for. If it is a band slipping then it won't help with that.
Valves can get sticky in the valve body so conditioners can also be used to help them work
better until the unit fully warms up. These old transmissions can be cold blooded but they usually work the best when fully warmed up. I would do a pressure test on it per the transmission manual for the unit you have. This will tell you whether it has enough to work or not if nothing else. If there is an internal leak, it won't fix itself.
If you haven't seen this then it may be a good read.
http://forums.y-blocksforever.com/Topic117674.aspx