speedo question

What I think you need, otherwise you may not be able to find the gear you want.
You should not have been able to pull the speedo cable out without removing the house and the metal clip in the green gear first.

MOPAR SPEEDOMETER TAIL SHAFT HOUSING 727 904 833 SPEEDO
68 69 70 AMX 727 TRANSMISSION CHANGEOVER CONVERSION SPEEDOMETER CABLE
or this
904 & 727 Transmission Speedo Housing Adapter Sleeve Torqueflite 6 8 Speedometer