I believe it's the wiring connector that is the main difference.
Try this:
1) Let it soak at the collet (the part around the shift shaft) with frequent doses of PB Blaster for a couple of days.
2) Make sure you remove both the collet nut and the adjusting screw up top.
3) Get two bits of flat bar stock - 1/8" or so inch thick, about 1" wide, and about a foot long (you can probably find these at the hardware store.) Slip them in between the NSS body and the transmission case, one to each side of the shift shaft.
4) Gently and alternately prise back and forth using the bar stock - the net effect will be to "wiggle" the switch loose. Eventually, you will get it to the point where you can hook your fingers behind it - it's yours at that point.
On reassembly:
1) Clean the shift shaft with a wire brush, especially down by the transmission case (be careful to not damage the shift shaft seal - it's a bear to replace.)
2) Paint the shift shaft with never-seez, especially near the transmission case.
3) Make sure the inside of the collet on the NSS is clean, then slip it into place.
Torque the collet nut to 62 pound-inches (about five pound-feet) and the adjuster screw to 14-15 pound-feet. No more! Make sure it's properly adjusted before you tighten the adjuster screw (have a helper watch the reverse lights. Make sure you're shifted into Reverse - the engine need not be running. Turn the switch until the reverse lamps come ON - mark that spot in some convenient manner. Continue until they turn OFF again - mark that spot. Position the switch midway in between the two marks. Verify proper adjustment by attempting to start in both Park and Neutral - it should work in both positions.)
If you manage to break the thing, let me know. I may want to get it from you...
