Speedometer Cable Assembly Parts - Borg Warner Overdrive

[Pilotdave]

I have a 1950's era Borg Warner overdrive (R10-B) in my SW Fordor. I'm looking for the bullet, shown in the attached photo, that connects the speedometer (square) cable/housing to the speedometer port on the overdrive unit. I'm also looking for the gear that connects the speedo cable to the drive gear inside the overdrive unit. I understand that the "standard" gear tooth count is 22, likely used for a 3.73 rear end. I have a high speed rear end so would likely need a lower tooth count to obtain accurate speedo readings.

So....any help with sources for these parts and advice on the needed gear tooth count would be greatly appreciated.