I have never heard the term "Shorty Scott" either, maybe the low profile fishing Scott motor? I have never been inside of them if my guess is correct.
The older 50’s Scott-Atwater & Firestones have a round nut with a collar which engages into the shift dog on a threaded shaft. As the shaft is moved up or downit moves the shift dog on either the prop-shaft or D-shaft[ to engage F.N.R pattern. The vertical shaft directly engages the shift dog for simple linkage. The earliier design has clevis assembly on the upper shift shaft to actuate the S-rod up & down directly into the prop shaft inner shift tube that fits inside the prop shaft much like Mercury or OMC that moves the dog to shift. Other later models have a clevis directly under the motor that must be disconnected in order to remove the powerhead for replacing the waterpump impellers as they are directly above the gearcase like the Mercury Mark 28, The impeller is above the gearcase like any OMC as well. in my gatherings./size]
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