Do searches here and on other sites. There is a lot on this topic. Example try "sag OD" here for a start. The Old Berb Club has info. Hot Rod Magazine did an article in April or May of 1970. Search on the H.A.M.B. The 3 &4 speed Saganaws involved used the same case. When removing the OD from the 3 speed you must also take the main shaft. Remove the 2nd/3rd slider. Put the 1st/2nd & 3rd/4th sliders in it's place. There is room. You must drill a hole in the rear of the case for the reverse kick out. Borg ODs don't like to run backwards! You can wire the governor to have OD in all forward gears at any speed. Panic pointed out that most of those ratios are fairly redundant. The main advantage of the 4 speed OD is the 4th over for the highway. Of all the '30s-60s cars and pickups that ran Borg ODs there are two basic models. The R-10 has 3 planetaries and the R-11 that has 4. The R-11 is said to be quite a bit stronger. The best combo I know of for strength is the Borg T-85 3 speed with R-11 OD used in some Studebakers and Ford pickups. The Saganaw 3 speed OD units are hard to find. The unique long shaft 12v solenoids for them are rare. Never throw away a Borg OD solenoid! They can be repaired.
