That coil will work. You can find a pulsed signal a few places. Either + or - can be pulsed. As long as the coil's magnetic field is interrupted causing the field to collapse. It is just easier to pulse the positive. Normally on an old school car you go off the existing ignition. It's hooked up so it kills a cycle and allows the cylinder to fill with gas, and then dumps it all into the exhaust. You won't get big fire like what a lot of pictures show; with fuel injected cars you get some flame, but not as much. It doesn't really work on catted exhaust either. I built an oscillator with a 555 timer, and had it trigger a relay which went to the positive side of the coil. To set the frequency I used a 0.1uF cap, and a potentiometer. That way it was variable, and I could find the right pulse to make it work best. You will have to fiddle with it to make it right. I didn't try splicing into one of coils. That was something I was unsure of.
Or you could probably just throw the switch back and forth really fast.
Can you please draw me up a diagram for the 555 timer, 0.1uF capacitor, and the potentiometer? I am going to throw it into a project box for easy disconnecting.