Most—but not all—HEI systems have the ignition coil mounted in the distributor cap. A control module and magnetic pickup are mounted in the distributor, in place of a conventional ignition system's breaker points and condenser.

Does a HEI distributor eliminate the coil?

The HEI distributor is an inductive-discharge-style ignition, but with the points replaced by a solid-state switching device called an electronic ignition-control module. The module works like an electrical switch, turning power on and off to the ignition coil. This, in turn, causes the coil to generate spark.

How does HEI distributor work?

The HEI distributor is still an inductive-discharge ignition, but exchanges points for an electronic device called a module. Since this system produces more voltage and amperage output than a point-type ignition, it requires a larger-diameter cap to prevent voltage crossfire inside the distributor cap.