Engine stalls going over speed bumps

If its fuel level related, driving at speed with higher rpm, the engine would be much more able to swallow a big gulp of raw fuel than at idle. It would also depend on how your jetting is, if its already super rich, fuel will defiantly kill the engine. while idling, dump a tablespoon of fuel down carb. That will eliminate or illuminate it being fuel related.

Many older vehicles electrical problems start at the bulkhead connector, where loom passes through the firewall. Pull the connection apart and clean up contacts, then coat thin film of dielectric grease on the contacts. You can also wiggle connector while idling.