I finally got around to taking my shifter apart. It didn't want to come apart. The top bracket is aluminum and the piece it threads to is steel. Apparently I didn't lube it when it went back together, not realizing that the shifter rotates on these threads in use. The threads in the top bracket are now ruined. I put it back together with a generous dose of Never-seeze. I hope it holds up until I can find a used bracket. They are not reproduced for the '54-up.
If you are putting one together I'd recommend a coat of anti seize on these threads.
