Mike, You possibly have a transition piece that could be when Lionel took over Ives, and from the sounds of it, it may have had a motor swapped, from the original. There are versions of the 1688 "Torpedo" that had motors that could be used in the 1681E. The 1688 throughout its full run did actually have three separate motors that were used. One version, that is most likely what you have, is the one with 12 spokes, (middle production), which calls for a spacer and screw to connect the linkage. That version of motor uses #264E-21N spacer, and #700E-45N screw. The "N" signifying nickel. Both parts are available, for that motor only, as compared to the first version with 8 spoke drivers, and Peened rod connection. The last version that was used on the 1688 torpedo, resembles a 1655/1656 motor, where it gets mounted with two long screws that pass through the body.
Remember we are talking about a 1681E and a 1688. Certain motors could be swapped between the two, as could the late 258, which also uses the similar motor. You will have to get it into your hands, and examine it closely, as to the motor used, and how the side rods are connected. Take photos, and I can identify it for you. I have three 1681's, and four 1688/E's, and am in the progress of figuring out the exact year each version is made, and what motor it used. The 1688 & 1688E, actually have 8 different castings from 1936 until the end at 1941/42. The rarest being the 1936 1688E with forward facing open windows in the cab, a square roof hatch molded into the casting, and a winged keystone, above the headlight, and just under the smoke plate. This was produced ONLY in 1936. The casting changed numerous times after that.
