[RichardJ]

>>It should readd 12vdc when running.

if it reads around 9...than that wire still has the in it between bulkhead connector<<

>>HEI dizzy and Pertronix modules require 12vdc vs the points using around 9vdc so they don't burn up quick. 9vdc will kill a HEI module<<

72SB, none of that is true.

If you remove the resistance wire, you should have 14 volts.
You should be within a couple tenths of the battery voltage, which should be close to 14 volts if the alternator is charging close to normal.

I have had my '67 since 1985 and for the last 33 years it has had an HEI powered with that white braided resistance wire still in place. Originally it had a coil-in-cap HEI as pictured in this thread. When I installed AC about 15 years ago, I installed an HEI with external coil for clearance under the compressor.

The white braided resistance wire (ballast resistor) will drop the voltage about 2 volts, but since you are actually starting with 14 volts, you should measure 12 volts at the HEI. If I recall, the last time I measured the voltage at my external HEI coil, it measured 11.8 volts and at the time, my alternator was going out. I haven't had reason to recheck it.

>>9vdc will kill a HEI <<. If that were true, anyone that has had a dead battery would have surely killed their HEI.

I experienced a CS130 alternator failure in my Corvette that had an HEI.
I drove 50 miles home with the BAT light ON and the instrument VM showing under 12 volts. It wasn't until the VM showed 8.5 volts that the engine began to sputter. It did not die, it sputtered into my driveway.

Over voltage can kill an HEI as well as many other automotive electronics. The Pertronics I , mentioned in this thread are very susceptible to any voltage close to 16 volts.