Flickering Lights

Just got finished making repairs to wires going to the bulkhead connector in my 1965 Dart. What I thought would be an easy fix (!!) to flickering interior lights, and headlights that would dim at idle and brighten when rpms went up. When I pulled both connectors from the bulkhead three wires for the forward light harness only had a few strands attached to the Packard terminals. Plus all of the wires had been spliced into other wires that the previous owner had run. These other wires were about eight inches long and were spliced into wires coming out of the harness. This meant there were two splices using squeeze unions. Way too many unions! I replaced both bulkhead connector plug-ins and installed new correct color wires, Packard terminals, and used solder seal wire connectors to connect wires to wiring harness. Also pulled headlights and buckets to clean ground for head lights.

Also replaced the voltage regulator as it was bad.

Connected everything back up, started engine and I have the same problem as before. At idle, 800 rpm, the interior dome lights and dash lights are steady. At about 1,200 rpm the dome lights begin to flicker and when parking/dash lights are turned on flickering continues. Turn on the headlights the flickering stops. Headlights off flickering comes back until engine returns to idle.

Got out ammeter to check voltage and make some other checks but can't get it to work.

Need a little help!!