head lights pulse after bypassing my bulkhead

I developed this issue recently too. I could hear the alternator field kicking on and off while the lights flickered. I figgered the regulator was bad so I installed a new one. Hmmmm, same condition. I then installed an old regulator I had in storage and still had the same problem. I ran a jumper wire to make sure the alternator and the rest of the car were all grounded the same and still had the problem. Then I ran a jumper from the battery positive to the 12 volt input to the regulator and everything was just fine--nice steady 14 volts. I found a 0.5V drop between the battery voltage and the voltage at the regulator input wire. All the wiggling of the bulkhead connector wouldn't clear it up so I put a relay in and all is well. The wire for the regulator and the wire for the ignition are the same one and I also installed a relay for the HEI. As long as I don't get any more resistance in that wire it appears all will be OK----but it's time to fix that voltage drop to avoid any other issues.