PROVE IT ! So you have a huge cable from the battery to your starter to carry a huge amperage, why do you have such a tiny conductor inside you spark plug cables? Where is your degree in electronics or your electricians license, or you degree in mechanical engineering? I challenge all of you to put up test equipment and see what happens and prove me wrong. What do you know about Watts LAW. AMPs x Volts = watts, test to see what the current draw of a coil and or your ignitions system is while running. DO THE MATH. PUT YOUR car's engine on a diagnostic scope and watch the output from the coil to the plugs. If you DO THE MATH you will prove to yourself that voltage is what jumps the spark gap not amps. The amps from a magneto is the primary current generated in the built in coil that is what makes a mag work in the first place. It has a self contained coil that steps up the voltage from low to High so it doesn't require an outside power source. Ohms law ? Amps divided by volts = resistance. Do some actual online research about coil turns ratio. Study some about loses in conductors, or how heat affect resistance. The only reason top fuel uses a magneto is because Nitro does not vaporize! The only way the fuel can be lit off is for the plugs to heat up red hot at the precise time start the burn. You cannot use glow plugs because that would ignite the fuel while the piston is still on the upstroke. Those mags generate around 50 amps at around 1k volts. Top fuel engines must run lower compression because the cylinders are filled with a near liquid fuel charge so if they had high comp there's no way they could even turn over without locking hydraulically. Again I challenge to be proven wrong about whether the voltage is lighting the spark or amperage in a gasoline engine. If the voltage isn't the critical issue than why are super high output voltage coils sold for racing? Do you homework and find out why such a low amperage can kill you when the voltage is high enough to push through the resistance of your body. It only take around 50 volts at around 0.2 amps to stop a heart beat if the power is applied continuously. Again, look at a diagnostic scope that will tell you how many volts it takes to jump the spark gap from your rotor to your spark plug wire terminals and how many volts are lost in the resistance of you wire then how many volts are required to jump the gap of your plugs under compression! Go ask and old time engine tuner that has spent his life time doing this like I have and see if he sides with you or not. Now if the resistance of your wires is a constant which it is, and the required voltage must increase because of compression which has already been established here, than by mathematical calculation the amps will increase. But that doesn't mean the amps are what does the work because if the coil cannot produce the higher voltage than there will be no spark and if there is no spark then there is no amperage because a close circuit pulls voltage down and the amps go up in which case the coil cannot produce those amps because the secondary windings are too small to carry that high current, which why coils are not made to deliver high amperage to the plugs, they deliver high voltage. Another reason there is such thick insulation on those tiny conductor spark plug wire, to keep that high voltage from arcing to the engine.