No, power only runs up the yellow to the coil when the starter is engaged, Better to power the HEI with a 12 volt switched wire from the firewall junction block. Are you using the original coil wire to power your HEI? The original wire is a resistor wire and will not give the necessary 12 volts to the HEI. You could replace the original wire with a non resistor wire or you could install a relay controlled by the resistor wire and have the power in wire run from the alternator/battery wire.