A 47 Plymouth (and nearly any Mopar before about 61 or so) has a very large diameter hollow splined shaft. None of the "newer" adapters are even close, they all have the steering shaft hole too small to fit the original shaft. I've made a few, they are a pain in the butt to make, and you pretty much have to hack up an original steering wheel to get a hub the fits to start with, then you modify that so the "modern" 3 bolt wheels can be attached to the old hub. Getting a horn to work is a project by itself. Gene