Putting the full 12V to the coil won't make it (the coil) fry immediately, but will shorten it's life a bit.
You said your ballast resistor measured at 1.8 ohms, but have you measured the resistance across the coil terminals? The coil has a weird thing called impedance (which changes with time that it's energized) and that makes it a little hard to narrow down. But I found this "External Resisted Ignition Coils have an internal resistance of 1.5 Ohms and when combined with the Ballast Resistor, you get a total resistance of 3.0 Ohms which is necessary for 12-Volt ignitions systems" on
this site. That implies that the ballast resistor should be 1.5 Ohms also. But I haven't seen specs for the offered ballast resistors except
this one from Speedway. Lower resistance of the ballast resistor would result in higher voltage into the coil.
