Trouble with underhood harness with HEI conversion

[TBONE1964]

This has got me so curious that I went out and checked my own truck (1972 Chevy 350 w/HEI and external regulated alternator (factory config)

Using a DVOM, I have 12.4 volts with key on engine off.
During the crank which is very short, I see a voltage drop to 10.8.
While running, I see between 13.6 and 14.1 volts at idle with no acc on or lights.

The battery voltage on the hot wire to the distributor for an HEI should be whatever the alternator is putting out at any given time.

I believe it is possible for a weak ignition module to require more than 10 volts to light the engine up. Is it 10 or 10.8 and is that enough to make a difference??

Normally when an HEI ignition module goes bad it is due to heat and not voltage.

I am curious to see what the fix is for you.