I recently aquired an HEI Ignition Coil. This is basically just a more powerful ignition coil. You can see the difference to the left.
Below are some of the results using the HEI.
Low Frequency Images:
 
 
 
 
 
 
High Frequency Images:
 
 
 
Video
Low Frequency Arc - 0.93mb
High Frequency Arc - 0.93mb