Hi Shanker what particular 70 Coronet you working on.I was thinking that dark blue bullet connector was for the key on activated power to the AC or Carb solenoid .Hows the heavilly optioned RT doing these days
The Vacuum retard connector I believe was flat similar to the alt field type connector.Ac or Idle solenoid seems more likely to the one you pictured
http://www.mymopar.com/66to71_wiring.htm