My original coil is bad and I am trying to find a good replacement and keep things stock. When reading into the coil specs, I found out the the original coil had a spec of 1.7-2.0 primary ohms and 3000-20000 secondary.
Most aftermarket coils seem to be 1.2 ohms on the primary side. Any feedback if that would cause any issues? I know there is a primary wire on the car going to the coil that maybe makes up for the difference in ohms, but I am not an electrical guy. THx.
There are 2 types of coils. coils one that have an internal resistance for use where you just run 12v to and a coil and one that doesn't have the internal resistance for cars that have a resistor wire or ballast resistor. Forgot the exact numbers but think they are around 1.7 and .7 respectively.
Are you still using points? If so, RockAuto has two AC Delco coils that should be perfect. Coils
As to operation, the 'RUN' ignition wire that goes to the coil + terminal is a resistor wire. It drops the 12 volts to 6 volts to extend the life of the points. The other wire is from the starter solenoid + terminal. That gives a full 12 volts to the coil for better starting. When the starter disengages, it goes back to 6 volts.
Before HEI came out, when I ran points, I used the Mallory Volt Master coil. It was huge and worked great. I also used the Mallory Super Condenser. It was so big it had to be mounted on the outside of the distributor body. The points lasted much longer and performance was improved greatly.
You can still get a Pertronix points eliminator kit that replaces the points with a solid state ignition, and a more powerful coil. That way it looks stock but is much better than stock.
I only use GM HEI. But we put a Mallory Unilite on a friend's '55 Chevy. [not magnetic but rather an infra-red system] We kept blowing modules because the owner had NO grounds from the engine to the car. After adding three dedicated ground straps, no more issues. That Unilite is still going strong 20 years later.
