Did you replace the wire from the ignition switch to the HEI when you upgraded to the electronic ignition? Depending on the year of your truck, there will either be a ceramic resistor on the firewall, or a nickel-chrome wire from the ignition switch to the original coil. Either way, the voltage to the coil would have been dropped to about 9 volts at the coil + terminal to prevent burning the points. The HEI needs full alternator voltage, about 14 V, to work right, and also a lot of amperage. The best bet is to run a #10 wire all the way from the ignition switch to the HEI coil's + terminal, and eliminate the small-gauge wire to the resistor, or the nichrome wire. It sounds like the heater blower is robbing voltage from the HEI, and the only way that can happen is if the wiring to the ignition switch from the battery, or the wire from the switch to the HEI is too small to carry the current load, or it's dropping the voltage available to the electronic ignition.
Jerry
Last edited by Hotrod Lincoln; 12/28/2009 2:44 AM.
