Check the voltage coming to the HEI from the ignition switch. If you haven't run a heavy-gauge wire all the way from the switch to the coil you're probably trying to run your HEI ignition system on about 9 volts. There will be a ceramic resistor, or a nickel-chrome wire from the ignition switch to the coil that drops the voltage to the original coil. That circuit MUST be bypassed for the HEI to work properly. Find the terminal at the back of the ignition switch that powers the coil in the run position, and install a #10 wire from there to the HEI coil input terminal. Just disconnect and tape off the power wire that went to the original coil.
Jerry

Last edited by Hotrod Lincoln; 12/07/2009 12:41 AM.
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