[40 Deluxe]

A note on "hot coils": A Super Duper Flame-Throwin' Bug Zappin' coil only produces enough voltage to fire the spark plug no matter what it's rated at! When the points open and the coil's primary field collapses, voltage rises in the secondary windings only until there is sufficient energy to jump the plug gap. Thus, if 5,000 volts is enough to produce a spark, 5,000 volts is all the coil will produce. Higher compression pressure and/or a larger plug gap requires more voltage so the plug may not fire until the secondary voltage rises to maybe 10,000 volts. The advantage of a Mega Trick Zap-Ya'-Good coil is the reserve capacity. If the plug gap or rotor gap wears larger than specs, the coil can still fire the plug. It will also handle higher compression than a stock coil.
On the down side, a hot coil draws more amps than a stocker. which amperage of course flows through he points. Therefore points don't last as long. Also, if the plug gap and/or rotor gap gets too large, you have a higher voltage flying around inside the cap which can lead to stray sparks jumping to ground, jumping to the wrong plug, or eating through the rotor.
With stricter emissions laws in the '70's manufacturers had to go to a leaner fuel mixture. It takes a larger plug gap to reliably fire a lean mixture, which requires a higher voltage coil, which requires more current, which burns points quicker. Thus we now have solid state, or electronic, ignition. We also have heavier and better insulated plug wires to contain that high voltage.