Electrical or ground issue?

A good crimper and leads is really really worth it.
Packard 56 male terminals are a close match for the bulkhead disconnects.
Packard 58 female terminals are a close match for the firewall side of the connector. PICO canada also sells Chrysler style female terminals.
For the connector seals, contact DMT.

Any distributer that ships to US that you know for the 58 female terminals?
The PICO site tells me they don't distribute outside Canada