HEI Canister Coils

The HEI system is designed to use a low primary resistance coil and the HEI e-core coils have 0.5 ohms of primary resistance.  Published coil design specifications (like inductance, etc) are difficult to find.  Primary resistance in aftermarket coils is often published but very few (none that we could find) canister coils have 0.5 ohms of primary resistance but the HEI system works fine with ancient points coils (like the 1.5 ohm NAPA ECH IC12 coil).

The energy stored in an ignition coil varies with its inductance and the square of current (ie, E = ½L * I²).  Although a canister coil can have a higher inductance (L), its higher resistance reduces current (I).  Coil energy varies with the square of the current times the inductance, so a lower inductance coil can supply more energy if the current builds faster. See ignition coil questions.

The main benefit of using a canister coil in your HEI system is that you would be able to continue using the high tension coil wire that's specified for your engine and the coil mounting bracket..The disadvantage of using a canister coil in your HEI system is that the canister coil's less efficient design will reduce the spark energy supplied to the spark plugs. Higher primary resistance (in general terms) will flow less current and the coil will therefore take longer to saturate.

There is much more to coils than resistance and, as a system, all of the components should be designed work together and individual components should not be selected on the basis of marketing hype. If you have a choice, use an oil-filled coil instead of an epoxy coil for better heat dissipation.

Canister coils with a low primary resistance are listed below.  The criteria for appearing on this list is purely based on low primary resistance and not reliability.   Do your own research about the experience of others using these coils.

Coil Buy Online
Pertronix Flame-Thrower II 45,000 Volt Canister Coils (Chrome), PN 45001

0.6 ohms
primary resistance
Pertronix Flame-Thrower II 45,000 Volt Canister Coils (Black), PN 45011

0.6 ohms
primary resistance
Pertronix Flame-Thrower II 45,000 Volt Canister Coils (Black Epoxy), PN 45111

0.6 ohms
primary resistance
Accel High Vibration Super Stock Coil, PN 8140HV

0.6 ohms
primary resistance
Accel Super Coil, PN 140001

0.7 ohms
primary resistance
MSD Blaster 2 Coil High Performance Coil - RED (PN 8202)

0.7 ohms
primary resistance
MSD Blaster 2 Coil High Performance Coil - BLACK (PN 82023)

0.7 ohms
primary resistance
Standard Motor Products, PN UF6

0.80 - 0.89 ohms
primary resistance
Standard Motor Products, PN FD476 (Coil)
Standard Motor Products, PN  S583 (Coil Connector)
[Ford Duraspark II Electronic Ignition System]

1.13 to 1.23  ohms
primary resistance

 

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