I bought an NOS kickdown switch to replace the reproduction one that I had to bypass. Below is a sketch of my side by side continuity checks. I found the two lower terminals do not have continuity on the reproduction switch, which would make the solenoid not engage. I do have continuity for those two terminals on the NOS switch.
The GM instruction shows to set plunger movement at 0.18 inches. That is what I did. I do not find a measurement in the Ford instruction. It seems reasonable to me that with the Ford switch being designed for under floor use the plunger should be able to be pushed all the way into its sleeve without bottoming out. That does seem to be the case for both the reproduction and the NOS switch.
I did not find anything in my checks of these switches that would cause an electrical short.
1950 GMC 100 Panel Truck, 1958 270, 3-spd Saginaw with BW OD, 3.73 12 Bolt Differential from a 1966 C10, Front Disc Brakes Bought it in pieces 9-1976, driving since 6-1978 Follow in the DITY
