The Main output Transistor on your ignition Box will only be rated at 4 amps continuous, so if you bypass the Ballast resistor you'll probably find you might exceed that all thought I've never checked it. A standard coil would be rated around the same current capacity
If you were going to bypass the Ballast put an amp gauge, it will have to be able to hold peak readings, on the 12 volt side of coil and that will give you an idea.

For a race car you should be able to get away with it but for the street you would be pushing it