Coil Voltage

I would expect the GM HEI to provide a hotter spark than the Chrys ign because it uses a more efficient E-core coil. Also GM specified 0.060" plug gaps, 0.080" for some engines, an indication of the available spark energy. The closed magnetic path of the E core design transfers more of the primary energy to the secondary winding, compared to the canister coil. Also, from what I have seen, E core coils have a lower turns ratio than canister coils. The MSD 8225 stock HEI replacement coil has a 70:1 TR, & the Blaster 2 canister coil has 100:1. In practical terms, all else being equal, the lower the TR, the more current in the spark. It is the heat in the current that ignites the A/F mixture. Of course, 60,000 volts [ high TR ] sounds much more impressive than 0.3 amps, so guess which one gets advertised & which ones the fools buy...
HEI use a current limiter inside the module to limit current to 5.5 amps. A very cheap & worthwhile upgrade is the MSD #63647 module that switches 7.5 amps, has a built-in rev limiter & makes a killer ign system.