.75v drop through bulkhead??

Noticed on my 68 RR voltage to the battery at hot idle is at 14.8 give or take .10, when i measure the voltage at the battery not running with key on.. its about 12.35v and coming back out at the blue with tracer going to the VR its about 11.55v. the ign switch is new and my amp meter in dash is still hooked up and terminals are tight. Where should i start to look? is this to much of a drop?