Hei conversion Intermittent start?

FWIW, I had 2 issues with my HEI conversions (3 of them).

1. swapped the pickup polarity from the distributor - caused a failed ignition module 2 x, and erratic timing another. It does matter.

2. Low voltage to the module. Caused intermittent starts. These HEI module require high voltage to run, (11+, in my experience), whereas the Mopar module requires 5+. I was losing a good bit of voltage through the bulkhead connectors, ignition switch, Ammeter, etc. While you may be getting 12+ volts when the keyed ignition is switched to the "run" position, when you engage the starter, it can easily dip below 12 volts, even into the 9's for an old battery. Thats why the Mopar ignition bypasses the Ballast resitior in the "crank" mode, and returns to that ballast circuit in the "run" mode. I installed a relay, switch on by the normal "run/start" voltage from the ignition, and hot wired directly to the started relay block. This helps eliminate the additional voltage drop through the bulkhead, etc, gaining an additional .2 to .5 volts. Problem solved for me!