Originally Posted by Chris's 46 / 515
it's mounted in the middle of the dash with 2 screws with a spring on the back that shifts a small gear box on the back of the speedomiter, let me know if you find a source
if the shifting lever is all you need look in a yard for a big truck that still has one that looks like yours. if you do find one take everything you can get your hands on for that system as spares should you need anything in the future.