DavidPackard wrote:
53 Cavalier . . . well done! I assume you still have the ‘215’ arm installed.

By the way, the operational description in ACDelco distributor patent US2187070 contains enough detail to conclude that both the high and low stops of the vacuum chamber are implemented by the geometry of the arm (‘operating member’ in Delco speak). The slot in the arm and its interference with the mounting bracket are the stops. There are no references to spring shims in the patent operational description. The subject patent is for the bracket made of sheet stock, but I suspect the cast bracket retained the same design intent.

dp