what voltage should I have at the coil

I have a 76 dodge truck with a 440/727 and everything is original. I drove it out of the garage and it was having an issue staying alive but would start up so I then tried to set the timing and then I moved the distributor around and made it improve. Now I go to start it this morning and no spark. after fiddling with for a few hours, I tried a new ECU, and ballast and coil and I even set the engine to TDC and made sure the rotor was pointing in the right direction and still no Sparky.

I did notice that it only has 3.47 across the coil with the key on.

What am I missing, is that even right to have 3.47 volts at the coil??